The bottom length of trapezoid is 4 and 9 respectively, and the diagonal is 5 and 12 respectively

The bottom length of trapezoid is 4 and 9 respectively, and the diagonal is 5 and 12 respectively


A complete ladder is added to form a parallelogram. The area of the trapezoid is half of the area of the parallelogram. A triangle like 5,12,13 will appear (one side of the parallelogram and one diagonal of each trapezoid). 5 ^ 2 + 12 ^ 2 = 13 ^ 2 is a right triangle, and the area is half of the parallelogram, which is equal to the area of the trapezoid
So trapezoid area = 5 * 12 / 2 = 30