Question

How do you find side `b` for a trapezoid?

Answer 1

`b=(2A)/h-a`

Explanation:

`A=(h(a+b))/2` is the formula to find the area of a trapezoid (trapezium), where A is the area, h is the height, a is one parallel side, and b is the other parallel side..

Solving for side `b` implies that you know the area A, side `a`, and the height.

Multiply both sides times `2`.

`2A=h(a+b)`

Divide both sides by `h`.

`(2A)/h=a+b`

Subtract `a` from both sides.

`(2A)/h-a=b`

Switch sides.

`b=(2A)/h-a`