Question

Suppose a triangle has two sides of length 2 and 3 and that the angle between those two sides is pi/3. What is the length of the third side of the triangle?

Please explain. Thank you!

Answer 1

Law of Cosines

Answer 2

a^2 + b^2 - 2abcos(C) = c^2

Answer 3

a and b are the given sides. C is the angle between them. c is the length of the side you are looking for

Answer 4

x^2 = 2^2 + 3^2 - 2*2*3* cos (60 degrees)

Solve for x.

Answer 5

Copy and paste this: x^2 = 2^2 + 3^2 - 2*2*3* cos (60 degrees)

Enter it here: http://www.wolframalpha.com/

Post what x cranks out to be. I got one of your options but you need to check.

@KJ4UTS

Answer 6

@Directrix I got x^2= 7. I also found someone else that asked this question:

http://openstudy.com/study#/updates/4e45b0170b8b3609c723c5d1

But the person who answered it used x^2=2^2+3^2-2*3*2*(cos pi/3)

Answer 7

pi/3 radians = 60 degrees

Answer 8

oh ok

Answer 9

Solve for x: x^2= 7

Answer 10

@KJ4UTS What is x?

If you follow my instructions on using Wolframalpha and scroll down, you'll see the answer.

Answer 11

I see square root 7

Answer 12

There it is, your answer.

Answer 13

oh ok thanks again that Wolframalpha looks really helpful.

Answer 14

You are welcome.