Question

Find the value of b.

http://static.k12.com/eli/bb/817/-1/0/2_37302_44974/-1/b0c7bc40f7e5f494498c3168c8648c065cd7076e/media/bfe2908f900d5d38a6300c7021ac9c8687fe2ffa/mediaasset_652080_1.png

Answer 1

You can use the Law of cosines for this. Do you know how to use that?

Answer 2

Nope. I kinda knew the other one but not this one.

And thanks for the help again.

Answer 3

\[b ^{2}=a ^{2}+c ^{2}-2(a)(c)cosB\]
Just plug the numbers in.

Answer 4

Are you doing trig or geometry?

Answer 5

Both.

Answer 6

Ok. Then you can use law of cosines. So just plug the numbers into that equation. Let me know if you have any questions using it.

Answer 7

@wrstlr3232 I got 23.19 for my answer. Is that correct?

Answer 8

Very close. You did everything right on the right side of the equation. This is where you are\[b ^{2}=23.19\]
There is one more step.

Answer 9

So would I do 23.19^2?

Answer 10

\[\sqrt{23.19}\]
Remember if you have a square on one side, you have to square root both sides. Think about it in relation to your picture. If one side is 8, one side is 6.5 and the other side is 23.19, the angle of the 23.19 would be huge. That's one way you can check your answer.

Answer 11

4.81.

Answer 12

Good job. If you think about it, 37degrees is pretty small. So the length of the side opposite to it, would have to be pretty small. Let me know if you have any other questions.

Answer 13

That would be the last one for now. Thanks again.