# Math Help - Law of Cosines

1. ## Law of Cosines

I dont know how to find the side!

Problem: a= 16 c= 12 B= 63degrees

I know the formula to use afterwards.

a^2=b^2 + c^2 - 2bc COS A

2. Originally Posted by topaz192
I dont know how to find the side!

Problem: a= 16 c= 12 B= 63degrees

I know the formula to use afterwards.

a^2=b^2 + c^2 - 2bc COS A
you're supposed to use the formula to find the side.

$b^2 = (16)^2 + (12)^2 - 2(16)(12) \cos 63$

use that to find the other side, b

3. Originally Posted by topaz192
I dont know how to find the side!

Problem: a= 16 c= 12 B= 63degrees

I know the formula to use afterwards.

a^2=b^2 + c^2 - 2bc COS A
Try this version of the formula:
$
b^2=a^2+c^2-2ac\cos B$

It's the exact same thing with the letters rearranged.

[EDIT]
Dang he beat me, lol.

4. lol yea i found a tutorial online thanks for your time though!