Question

What is the cos of angle B?

Answer 1

im drawing the picture right now.

Answer 2

cosine = adj/hyp

Answer 3

5/13

Answer 4

My phone doesn't have the negative cos so i cant get the answer.

Answer 5

don't you have to do the negative cos because you are trying to find a variable?

Answer 6

\[\cos = (5/13)=0.99997746\]

Answer 7

did i help you?

Answer 8

Cosine is adjacent over hypotenuse.
Cos(B) = 5/13

Answer 9

no need for law of cosines?

Answer 10

No.. why? You know all the sides.

Answer 11

Blah, nevermind. lol.

Answer 12

Yea, don't overcomplicate things

Answer 13

As per request.. solution using the law of cosines:

b^2 = a^2 + c^2 - 2a*c*Cos(B)

Answer 14

\[\large \cos (B) = \frac{a^2+c^2 -b^2}{2ac}\] right?

Answer 15

Yea

Answer 16

12^2 = 5^2 + 13^2 - 2*5*13*Cos(B)
144=25+169-130Cos(B)
144-194 = -130Cos(B)
-50 = - 130 * Cos(B)
Cos(B) = -50/-130 = 5/13

Answer 17

Happy?

Answer 18

\[\cos (B) = \frac{25+169-144}{2(5)(13)}\]\[\cos(B)= \frac{5}{13}\]

Answer 19

:D yes.