A new dam being built has the shape of a trapezoid. The length of the base at the bottom of the dam is 2 times the height.
The length of the base at the top of the dam is times the height
minus 30 feet.
5
a. Write an expression to find the area of the trapezoidal cross
section of the dam.
b. If the height of the dam is 180 feet, find the area
of this cross section.