Question

Find the area of a triangle with sides of length 7 and 9 and included angle 72 degree.

Answer 1

$a=7,b=9,\gamma=72^o \\ \\h_a=b\sin{72^o}=8.56 \\ \\A= \frac{ah_a}{2} = \frac{7\times8.56}{2}= 29.96$