What's the area of this trapezoid if the top width is 15, the bottom width is 20, and the height is 9?

The area (A) of a trapezoid is defined as:
\(A=\frac{1}{2}\left(b_{1}+b_{2}\right) h\)
Using the variables in this problem \(\left(b_{1}=15, b_{2}=20, h=9\right)\) that's:
\(A=\frac{1}{2}(15+20) \times 9\)
\(A=\frac{1}{2}(35) \times 9\)
\(A=\frac{1}{2} 315\)
A = 157.5