Answer: 141.12 in²
Step-by-step explanation:
Separate into two triangles where the height extends from the 147 degree angle to the 28.8 in side.
cos57 = A/18
A = 9.8 in
Plug into the following formula:
[tex]\frac{1}{2}[/tex]bh = [tex]\frac{1}{2}[/tex](28.8)(9.8) = 141.12 in²
