A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 4 years ago
For the given points P,Q.R, find the approximate measurements of angle PQR. P: (1,4), Q: (2,7), R: (2,2)
anonymous
 4 years ago
For the given points P,Q.R, find the approximate measurements of angle PQR. P: (1,4), Q: (2,7), R: (2,2)

This Question is Closed

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0have to solve it by dot products in calc 3

phi
 4 years ago
Best ResponseYou've already chosen the best response.1Mertsj has already figured out the lengths of these vectors

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0yea but how do you go about to dove this? i have no clue? i am trying all kinds of different things

phi
 4 years ago
Best ResponseYou've already chosen the best response.1First, let me fix it. we want PQR \[(\overrightarrow P \overrightarrow Q)\cdot (\overrightarrow R \overrightarrow Q)= \overrightarrow P \overrightarrow Q\overrightarrow R\overrightarrow Q\cos\theta\]

phi
 4 years ago
Best ResponseYou've already chosen the best response.1I assume you know how to find PQ and RQ : subtract corresponding elements I'll do PQ (1,4)  (2,7)= (12, 47)= (1, 11)

phi
 4 years ago
Best ResponseYou've already chosen the best response.1the length of a vector (x,y) =  (x,y) = sqrt(x*x + y*y)

phi
 4 years ago
Best ResponseYou've already chosen the best response.1a dot product of (x,y) and (a,b)= ax+by

phi
 4 years ago
Best ResponseYou've already chosen the best response.1Did you find the magnitude of RQ (and PQ) ?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0you just square them right?

phi
 4 years ago
Best ResponseYou've already chosen the best response.1the length of a vector (x,y) =  (x,y) = sqrt(x*x + y*y) that means you take the first number , square it, square the 2nd number, add together then take the square root

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0pq = sqrt (121) rq = sqrt (41)

phi
 4 years ago
Best ResponseYou've already chosen the best response.1ok , now the dot product of (pq) dot (rq) (1,11) dot (4, 5)

phi
 4 years ago
Best ResponseYou've already chosen the best response.1dot product of (x,y) and (a,b)= ax+by

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0so its (1*4 + 11 * 5)

phi
 4 years ago
Best ResponseYou've already chosen the best response.1yes, but that is just a number=?

phi
 4 years ago
Best ResponseYou've already chosen the best response.1yes. now put it all together (pq) dot (rq) = pq  rq cos A we now everything except A.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0but that will only give us one angle right?

phi
 4 years ago
Best ResponseYou've already chosen the best response.1This gives us the angle formed by pq and rq pq is a vector with its base at q. same for rq dw:1328106371363:dw

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0yea but we need three angles angle P=? , angle Q=? , and angle R =?.

phi
 4 years ago
Best ResponseYou've already chosen the best response.1find the approximate measurements of angle PQR this means the angle from P to Q to R in other words, Q is the vertex . Just 1 angle

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0this is problem 60 in the book. problem 61 is the same question but P: (0, 1, 3), Q = (2,2,1), R= (2, 2, 4) and answer given in the back is p=78.8 degrees , q= 47.2 degrees and r = 54.0 degree

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0thats's why i am confused

phi
 4 years ago
Best ResponseYou've already chosen the best response.1First, what did you get for angle pqr?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0i can't solve it. sorry i am really bad at it

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0so its 59 = sqrt (122) * sqrt (41) cos a

phi
 4 years ago
Best ResponseYou've already chosen the best response.1the contraction of "it is" is "it's" (sorry , pet peeve!)

phi
 4 years ago
Best ResponseYou've already chosen the best response.1to find cos a, divide both sides of the equation by (sqrt(122)*sqrt(41))

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0lol sorry i am nervous right now

phi
 4 years ago
Best ResponseYou've already chosen the best response.1you can type acos(59/(sqrt(122)*sqrt(41))) in degrees in the google search window to find the angle or use a calculator.

phi
 4 years ago
Best ResponseYou've already chosen the best response.1that's in radians. I would do 2 things. first, use a few more digits in your answer to 59/(sqrt(122)*sqrt(41)) (because your book is finding the answer rounded to tenths of a degree) then use degree mode with the calculator or type in degrees when using google

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0oh k i get 33.5 degrees

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0but thats just one angle. how do i find the other ones

phi
 4 years ago
Best ResponseYou've already chosen the best response.1If you want the angle with vertex P, which we would name as angle QPR (or angle RPQ), form the vectors (qp) and (rp) and do the same thing: (qp) dot (rp) = (qp) (rp) cos P

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0would you help me with other question that i posted?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0and to find the third angle, i could add two angles and make it equal to 180 right?

phi
 4 years ago
Best ResponseYou've already chosen the best response.1btw, notice that (qp) = (pq), so just negate each element in your (pq) vector , which you already know. And of course the length of (qp) = length (pq)

phi
 4 years ago
Best ResponseYou've already chosen the best response.1Yes, the third angle = 180  sum(other two) but it doesn't hurt to do the dot product.

phi
 4 years ago
Best ResponseYou've already chosen the best response.1as a check, and to get comfortable with the procedure

phi
 4 years ago
Best ResponseYou've already chosen the best response.1when you post your answers I'll double check them.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0what would be the setup to find the last angle?

phi
 4 years ago
Best ResponseYou've already chosen the best response.1yes, looks good. for the last angle, the vertex is R look at how you did the previous two, and look for the pattern. post your setup

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0(pr) * (qr) = pr qr cos a ?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0i get 114.8 for the last one

phi
 4 years ago
Best ResponseYou've already chosen the best response.1notice that 180  (31.8+33.5)= 114.7 which matches your result within rounding error.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0can you please help me with my other problem?

phi
 4 years ago
Best ResponseYou've already chosen the best response.1repost it. this one is long enough
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.