Question

In AABC, a = 13, b = 14, and c = 18. Find m/A.
B
A
39.5
с
b
a

Answer 1

Explanation:

Using the Law of Cosines,

`a^(2)=b^2 + c^2 - 2bc \cos A\\\\13^(2)=14^(2)+18^(2)-2(14)(18) \cos A\\\\-351=-504 \cos A\\\\\cos A=(351)/(504)\\\\A=\boxed{\cos^(-1) \left((351)/(504) \right)}`