Compute the area of a trapezoid with bases 10 cm and 6 cm and height 4 cm.

• A. 28 cm^2
• B. 30 cm^2
• C. 34 cm^2
• D. 32 cm^2

Answer: (D)

The area of a trapezoid comes from multiplying its height by the average length of the two bases. This works because the width changes linearly from one base to the other, so the average width over the height represents the area of a rectangle with the same height.

Compute the average of the bases: (10 + 6) / 2 = 8. Multiply by the height: 8 × 4 = 32.

So the area is 32 square centimeters. The other numbers come from using an incorrect base average or misapplying the height, whereas the correct method uses the average of the two bases.