The area of a trapezoid is given by the formula A=h/2 (a+b).

Solve the formula for b.

(2A) / h - a = b

Step-by-step explanation:

A = [h (a+b) ]/2 I rewrote the formula, because h and a+b are in the numerator.

2A=h (a+b) Multiply both sides of equation by 2

(2A) / h = a+b Divide both side by h

(2A) / h - a = b Subtract a from both sides