FTCE General Knowledge Math Practice Test - Prep, Practice Questions & Study Guide

The formula for the perimeter of a trapezoid is indeed the sum of the lengths of all four sides of the trapezoid. This is due to the geometric nature of the shape, where the perimeter, by definition, is the total distance around the figure. Therefore, to find the perimeter, you would add the lengths of the two parallel sides and the lengths of the two non-parallel sides together. This is why the correct answer is the sum of the lengths of the sides.

The other options provided pertain to different geometric concepts. One option represents the formula for the area of a trapezoid, which involves the heights and the lengths of the two parallel sides. Another option is the formula for the area of a rectangle, and the last option refers to the volume of a pyramid. These do not apply to calculating the perimeter of a trapezoid and highlight the specifics of what defines the perimeter versus area or volume in geometry.