Question

The formula for a trapezoid relates the area A, the two bases, a and b, and the height, h.

Answer 1

I'm assuming the original equation is $A= \frac{h(a+b)}{2}$
Step 1: Multiply both sides by 2 to eliminate the denominator
Step 2: divide by h
Step 3: subtract a
$b= \frac{2A}{h} -a$