how do i find a point that is perpendicular to another line if I know what the equation of the first line is and i know what the slope is.

- anonymous

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- jim_thompson5910

say the given slope is 2/3
Any line perpendicular to the given line will have a slope of -3/2
One way to remember this is to think "flip the fraction and flip the sign"
So....
Start with 2/3 (given slope)
flip the fraction: 2/3 ----> 3/2
flip the sign: 3/2 ----> -3/2
Therefore, if the given line has a slope of 2/3, then the slope of any perpendicular line is -3/2

- anonymous

Im sorry I dont really understand this how do I do the whole problem so that I can do the next 3

- jim_thompson5910

what's the full problem again?

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## More answers

- jim_thompson5910

what's all that you're given?

- anonymous

If the line h passes through the two points (1, 2) and (3, 6) This is the given information to solve the two problmes, here is the questions
What is the slope of the line h passing through the two points?
What is the equation of the line h passing through the two points?
If line g passes through point (2, 2) and is perpendicular to the line h, then what is the equation of
line g ?

- jim_thompson5910

how far did you get here?

- jim_thompson5910

were you able to find the slope of the line h?

- anonymous

i got that the equation of line h passing through is Y=2x

- jim_thompson5910

good

- jim_thompson5910

so the slope is 2 or 2/1

- anonymous

and the slpe is 2

- jim_thompson5910

so what's the perpendicular slope?

- anonymous

If line g passes through point (2, 2) and is perpendicular to the line h, then what is the equation of
line g ? this is the one that I am having trouble with

- jim_thompson5910

if the slope is 2 or 2/1
then what's the perpendicular slope?

- jim_thompson5910

hint: look at my steps in my very first post

- anonymous

I really do not like math i am so slow to learn this stuff

- jim_thompson5910

that's ok

- jim_thompson5910

do you see how in my example (in my first post) where I went from 2/3 to -3/2
did that all make sense?

- anonymous

I was thinking that Y=-1/2X

- jim_thompson5910

the perpendicular slope is -1/2, that's a good start

- jim_thompson5910

so m = -1/2

- jim_thompson5910

the point line g goes through is (2,2)
so this means that x = 2 and y = 2

- anonymous

but how do I figure this out IM not so good with all these formulas can you dumb this down a bit for me.

- jim_thompson5910

now we turn to y = mx+b and plug in m = -1/2, x = 2 and y = 2
y = mx + b
y = (-1/2)x + b ... plug in m = -1/2
2 = (-1/2)*(2)+ b ... plug in x = 2 and y = 2
2 = (-1/2)*(2/1)+ b
2 = (-1*2)/(2*1)+ b
2 = -2/2 + b
2 = -1 + b
2 + 1 = b
3 = b
b = 3
Therefore, m = -1/2 and b = 3
So the equation of line g is
\[\large y = -\frac{1}{2}x + 3\]

- jim_thompson5910

let me know what you think

- anonymous

Im still trying to undersdand MX+B
i know that those numbers have a funtion and you need to know what those are to move on right?

- jim_thompson5910

m is the slope of the line
b is the y-intercept of the line

- anonymous

that is what my book says

- jim_thompson5910

x and y are variables
they can be any number
the value of y will depend on what x is

- anonymous

and you need to do some math to find the slope and I needed to know the other parts to do this problem right?

- jim_thompson5910

the usefulness of y = mx+b is that you can find the equation of any line if you know the slope and any point on the line

- anonymous

are you a teacher?

- jim_thompson5910

I'm a student learning to become one
so yes and no

- jim_thompson5910

and yes, you need to figure out the slope before you can move on

- anonymous

I think I gave that to you right, which I got 2 for that

- anonymous

how did you find out y is that one of the four numbers that you use to plot the line?

- jim_thompson5910

what do you mean?

- jim_thompson5910

yes the original slope (ie the slope of h) is 2

- anonymous

I am trying to understand the whole equation I hate just getting the answers to a problem and not know how to solve it you know, i was wondering what Y is and how do you get the numbers for all the letters in this math problem.

- anonymous

ive been on google all night looking up how to solve for all these math problems and have been comming up with the right answers but have been struggling to understand them.

- jim_thompson5910

y is a variable and it is not assigned a fixed value like m or b are

- jim_thompson5910

when you say y = 2x, you are saying "for each x you plug in , you double the value to get y"
so that means if you plug in x = 1, you get y = 2 (double 1 to get 2)
when you plug in x = 13, you get y = 26 (double 13 to get 26)

- jim_thompson5910

this produces a bunch of points, you plot these points, then draw a line through them to graph y = 2x

- anonymous

My problem is im trying to do these in my head I dont have a calculator or graphing paper :(

- jim_thompson5910

well if you can't do them in your head, use pencil and paper

- jim_thompson5910

you can use google as a calculator
ex: type in "2*3 + 10" into google without quotes and it will spit out the result like a calculator

- anonymous

i was trying to graph the lines to visualize them

- jim_thompson5910

and if you need a program to help you graph, I recommend geogebra
http://www.geogebra.org/cms/en/

- jim_thompson5910

to graph the lines, you just need two points
so one point on y = 2x is (1,2)
another point on y = 2x is (2,4)
plot the two points (1,2) and (2,4) and draw a straight line through them
this will give you the graph of y = 2x

- anonymous

here is the next part to the questions that you have helped me with,
If line F is parallel to the line H, and line F has Y-intercept 5, what is the equation of line F?
can you walk me through all the steps and ill write them down as we go i really want to lean this type of math.

- anonymous

im guessing it is using the answer to the last question that you helped with.

- jim_thompson5910

what is the slope of line h

- jim_thompson5910

yes it all builds up

- anonymous

ok let me see what I have for that. I got 2 for that.

- jim_thompson5910

so m = 2

- anonymous

ok got it.

- jim_thompson5910

the y-intercept is given to be 5, so this means b = 5

- jim_thompson5910

so we go from
y = mx+b
to
y = 2x + 5

- jim_thompson5910

that's the equation of line f

- jim_thompson5910

why is the slope 2? because parallel lines have equal slopes

- jim_thompson5910

slope of h is 2
line f is parallel to h
so the slope of line f is also 2

- anonymous

do you have a aol sceen name i could add you to my list to ask another question some time?

- anonymous

im still writing down your words for the problem right now.

- jim_thompson5910

I don't use AOL messenger, but I do use yahoo messenger

- anonymous

oh i dont have that installed now. but you can email me at doclovett@yahoo.com

- anonymous

So Y and B are the same as 5? is this correct.

- jim_thompson5910

b is 5, y is a variable
y is allowed to change

- anonymous

so y is an unknown

- jim_thompson5910

yes

- jim_thompson5910

it represents any number pretty much at this point
the same can be said for x

- anonymous

ok

- anonymous

damn now I have to deal with a triangle and COS and TAN

- anonymous

thanks for your help. I am trying to figure out angles with Sin A=15/17

- jim_thompson5910

check out this page
http://openstudy.com/updates/521ef027e4b0750826e0c91a
I think you (zombiebacon) and the user jaidyn206 are taking the same course. I could be wrong.

- jim_thompson5910

so you guys can set up a study session if that is true

- anonymous

yeah she is in my class im talking to her in aim she is ahead of me in the class on different questions.

- jim_thompson5910

I gotcha

- anonymous

what does sin A=15/17 mean

- anonymous

i just wasted a few min figuring out degrees in angles for nothing didn't I?

- jim_thompson5910

if you have a right triangle that looks like this
|dw:1377760654037:dw|

- jim_thompson5910

then the sine of the angle A is equal to the opposite side (15) over the hypotenuse 17
ie, sin(A) = 15/17

- jim_thompson5910

no I don't think you wasted your time

- anonymous

how do I draw a picture to show you

- jim_thompson5910

use the draw button below the text box

- anonymous

##### 1 Attachment

- jim_thompson5910

that works

- anonymous

i attached the jpg of the triangle
sin is A=15/17

- jim_thompson5910

ok so what's question referring to the picture?

- anonymous

what is the length of side a?

- jim_thompson5910

sin(A) = 15/17 tells us that the opposite side is 15 (the side opposite angle A)
so a = 15

- anonymous

I have not read what sin means yet so that is where I am at on that.

- jim_thompson5910

17 is the hypotenuse, which is opposite the 90 degree angle
the hypotenuse is always the longest side

- jim_thompson5910

so c = 17

- jim_thompson5910

I recommend reading up on that lesson

- anonymous

last week we learned about a^=B^=c^
and i was trying to understand that im sorry for the dumb retricequestions here but I have done nothing but struggle this whole moth with this class.

- jim_thompson5910

they're not dumb

- jim_thompson5910

I think you meant to say a^2 + b^2 = c^2 no?

- anonymous

yes the squared

- jim_thompson5910

that's the pythagorean theorem

- anonymous

we were learning about the length of the legs and bases and finding out the missing piece by using that equation

- jim_thompson5910

so if you have a right triangle, and you only knew 2 of the 3 sides, you can use the pythagorean theorem to find the missing side

- anonymous

I ws trying to use that for these last questions

- jim_thompson5910

what information is given? what do you know so far about the sides?

- anonymous

For question 14 and 20, refer to the right triangle Î” ABC with
sides a, b, and c. If sin A = 15/17

- jim_thompson5910

what are a and c

- anonymous

using the picture I sent you and this we have to answer our questions.

- jim_thompson5910

I know, what are the values of a and c

- anonymous

unknown.

- anonymous

14. What is the length of side a? 14. A) 15 B) 8 C) 17 d) 10
15. What is the length of side c? 15. A) 15 B) 8 C) 17 d) 10
16. What is the length of side b? 16. A) 15 B) 8 C) 17 d) 10
17. What is the measurement of âˆ Î‘? 17. Î‘) 61.930
Î’) 28.070
C) 64.800
D) 25.200
18. What is the measurement of âˆ B? 18. A) 61.930
Î’) 28.070
C) 64.800
D) 25.200
19. What is cos A? 19. A) 0.47 B) 0.53 C) 0.88 D) 2.13
20. What is tan A? 20. A) 1.875 B) 2.125 C) 1.13 D) 0.53

- anonymous

those are the questions and im not even supposed to post them on any site or i will get in trouble.

- anonymous

but im really struggleing to understand this

- jim_thompson5910

why can't you post them?

- anonymous

my school made me sign a paper for all materials so that they can not be posted on the internet so people can't cheat and just get the answers.

- jim_thompson5910

I see

- anonymous

I am actually trying to learn this stuff and there are some guys that just cheat and look up the ansers on the net.

- anonymous

we also sign an acidemic dishonesty policy paper.

- anonymous

this class is costing me 5000 dollars and I really do not ant to fail it.

- jim_thompson5910

these are the same questions jaidyn206 just went through
have you asked jaidyn206 for help?

- anonymous

I dont want to get just the answers from her.

- jim_thompson5910

no I'm not saying that, like I'm saying ask her questions and such

- anonymous

we are both very new to this type of math and she is having trouble walking me through it since she is unsure of it herself.

- jim_thompson5910

alright

- jim_thompson5910

which side is opposite angle A

- anonymous

ok oppisite of anble A is little a right.

- jim_thompson5910

yes

- anonymous

because the longest ine the hypotanuse is a

- jim_thompson5910

sine is opposite over hypotenuse, so...
sin(A) = 15/17 means that a =15 and c = 17
the opposite side is a
the hypotenuse is c

- anonymous

and it is also the base i believe.

- anonymous

the little bulb just lit up in my head just now :D

- jim_thompson5910

that's great

- jim_thompson5910

glad it did

- jim_thompson5910

use these values of a and c to find b

- anonymous

so 17 the legnth is 17 of side c

- jim_thompson5910

yep

- anonymous

now here is where i get confused are they using inches or what for 15 and 17?

- jim_thompson5910

don't worry about the units

- anonymous

I know that inside the triangle it is supposed to be 180 degrees

- jim_thompson5910

a = 15
b = unknown
c = 17

- jim_thompson5910

a^2 + b^2 = c^2
15^2 + b^2 = 17^2
solve for b

- anonymous

now how to i use this to answer the question are we using degrees to answer this?

- jim_thompson5910

we're finding the side length b, not the angle B

- anonymous

oh snap, ok

- jim_thompson5910

so we don't need to worry about degrees

- anonymous

because i did the angles and it comes up to angle B is 15 degrees angle C is 90 degrees and angle A is 75 degrees.

- anonymous

I dont need any of that do I?

- jim_thompson5910

that's a bit off

- jim_thompson5910

angle C is 90 degrees though, that's correct

- jim_thompson5910

A and B are off though

- anonymous

289-225=64 and that squared is 8 right?

- anonymous

so I should have 8 as my answer.

- jim_thompson5910

b = 8 is correct

- jim_thompson5910

so the 3 sides are:
a = 15
b = 8
c = 17

- anonymous

my angles are angle A is 62, angle B is 28 and angle c is 90 do I use these to answer the questions now?

- anonymous

to find the measurement of A do i just add A,C and A,B?

- jim_thompson5910

you rounded too far, but you have the right idea

- anonymous

doesnt it have to equal 180 degrees?

- jim_thompson5910

yes the 3 angles have to add up to 180 degrees

- jim_thompson5910

but angle A isn't exactly 62 degrees

- anonymous

the closest answer to mine is 61.93

- jim_thompson5910

that's the correct answer
hopefully you see how to get it

- anonymous

but how do you get the decimal when i was getting whole numbers that is what is messing me up?

- jim_thompson5910

how did you get 62?

- anonymous

Im using a plastic protractor and paper to get my answers.

- jim_thompson5910

i see

- anonymous

the half moon thing is called a protractor right?

- jim_thompson5910

yes it is

- anonymous

it only has lines and not decimals on it.

- anonymous

and whole numbers.

- jim_thompson5910

on this page here
http://openstudy.com/study#/updates/521ef027e4b0750826e0c91a
I explain how to find angle A

- anonymous

are you still there it says i lost connection?

- jim_thompson5910

yeah I am

- jim_thompson5910

look on that page and I explain how to find A

- anonymous

well when i did my angles with my protractor it was within the margin for the answers on the paper for me and I am picking the closestes.

- jim_thompson5910

on that page, I explain how to use google as a calculator to get the answer

- jim_thompson5910

there's no need to use a protractor
keep in mind that the figure is usually NOT to scale

- jim_thompson5910

so it's a very bad idea to use a protractor, but I can see why you're using it

- anonymous

Im not that good at math so I used the protractor and drew it on paper to figure out the answer and got the closest to it.

- jim_thompson5910

well you can't rely 100% on the image alone

- anonymous

but since they are not whole numbers i need to look at the math style you showed me.

- jim_thompson5910

yes look that page over once more

- anonymous

ok how do I do this without a calculator I dont have one of those just the windows one.

- jim_thompson5910

its ok, google acts like a calculator

- jim_thompson5910

so even if you don't have one, you can have access to a free one

- anonymous

that is cool

- jim_thompson5910

sin(A) = 15/17
A = arcsin(15/17)

- jim_thompson5910

type "arcsin(15/17) in degrees" without quotes into google to get
https://www.google.com/search?q=arcsin%2815%2F17%29+in+degrees&ie=UTF-8

- anonymous

OK thanks for the help I am going to get some rest I need to get up and work on my paper tomorrow.

- jim_thompson5910

you're welcome

- anonymous

do i need to close this thread

- jim_thompson5910

its ok, either way is fine
usually yes, you are supposed to close a question when you are done with it

- anonymous

ok i will close it thank you for your help. good night.

- jim_thompson5910

you're welcome, good night

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