The formula for a trapezoid relates the area A, the two bases, a and b, and the height, h. A=h (a+b) 2 Solve for b.

I believe the right equation for determining the area of a trapezoid is as below,

A = h (a + b) / 2

To determine the expression for b which is the length of one of its bases, we multiply the equation by 2.

2A = h (a + b)

Then, divide both sides of the equation by h,

2A/h = a + b

Then, subtract a from both sides of the equation,

2A/h - a = b

Lastly, interchange the sides of the equation to reveal the answer.

b = 2A/h - a