# Thread: use the cosin forumla to solve the angles of a triangle

1. ## use the cosin forumla to solve the angles of a triangle

a obtuse triangle with length ab=24 bc=36 and ac=49 use cos forumla to find its angles

help plz...

2. Cos rule: $c^2 = a^2+b^2-2ab \cos(C)$

Plug and chug to find one angle then you can use the sin rule to find the second

3. Originally Posted by antikv
a obtuse triangle with length ab=24 bc=36 and ac=49 use cos forumla to find its angles

help plz...
Law of Cosines -- from Wolfram MathWorld

Kind regards

$\chi$ $\sigma$