Answer
Find out the length of the second parallel side.
To prove
Formula
Where a , b are the parallel sides of trapezoid and h is the height of the trapezoid.
As given
The area of a trapezoid is 132 cm².
The height is 12cm and the length of one of the parallel sides is 9cm.
Here h = 12cm
a = 9cm
Put in the formula
132 × 2 = 9 × 12 + 12b
264 = 108 + 12b
264 - 108 = 12b
156 = 12b
b = 13cm
Therefore the length of the second parallel side is 13cm.