Not 100% sure looking for clarity
A source of laser light sends rays AB and AC toward two opposite walls of a hall. The light rays strike the walls at points B and C, as shown below:

- anonymous

- Stacey Warren - Expert brainly.com

Hey! We 've verified this expert answer for you, click below to unlock the details :)

- jamiebookeater

I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!

- anonymous

What is the distance between the walls?
80 m
180 m
90 m
100 m

##### 1 Attachment

- anonymous

@freckles

- anonymous

@SolomonZelman

Looking for something else?

Not the answer you are looking for? Search for more explanations.

## More answers

- anonymous

@Owlcoffee

- anonymous

@Vocaloid !!

- Vocaloid

alright, let's split the distance between the wall into two pieces, A and B, ok?
we're going to solve for A and B using trigonometry
|dw:1435783301582:dw|

- Vocaloid

|dw:1435783435188:dw|

- anonymous

I got 90m

- anonymous

?

- Vocaloid

as the final answer, or for A?

- anonymous

as for the final answer? what do you think it is?
I got 90m

- Vocaloid

uh, that's not quite right, can you try solving
cos(60) = A/40 for A?

- anonymous

i dont belive its B or D
is it A then?

- Vocaloid

we'll find the answer in a minute, hold on
if cos(60) = A/40, then what is A?

- anonymous

80m?

- Vocaloid

not quite...
cos(60) = A/40
what happens when you multiply both sides by 40?

- anonymous

180?

- Vocaloid

A = 40*cos(60)

- Vocaloid

plug that into your calculator and tell me what you get.

- anonymous

60 * 40 = 2400

- anonymous

sorry im bad at this

- Vocaloid

cos(60), not 60

- Vocaloid

look for the cos() button

- anonymous

i got 100

- Vocaloid

use this calculator and type in 40 * cos(60)
http://web2.0calc.com/

- anonymous

20

- Vocaloid

much better, lets move on to the next part...
|dw:1435784134047:dw|

- Vocaloid

ok, we can use a different trigonometric ratio, tan(45) = opposite/adjacent = 80/B
tan(45) = 1, so
1 = 80/B, so B = 80

- anonymous

Okay so the answer is A than?
I think i understand

- Vocaloid

no, please hold on...

- Vocaloid

|dw:1435784284536:dw|
going back to the original diagram, the distance across the wall is A + B
A = 20
B = 80
so what is A + B?

- anonymous

100m

- Vocaloid

right

- anonymous

thank you so much you made my day <3

- anonymous

Actually, you would subtract A (80) and B (20) to get 60 as your true answer. I just took the test and got that right.

Looking for something else?

Not the answer you are looking for? Search for more explanations.