write a formula

Question

write a formula for the given measure. let a represent the area in square ft, and h represents the height in ft. the area of a trapezoid with base lengths of 7 ft and 11 ft

Answer 1

Trapezoids seem like they should be difficult, don't they? Actually, the idea is easy. They think they are rectangles, but they can't decide whether the larger or smaller base should count, so they average them instead:

A = (b + B) / 2   * h

You didn't give a value for h, so that must remain a variable, but the rest will be:

A = (7 + 11) / 2  * h

A = (18)/2  * h

A = 9h

Ta-da!