FTCE General Knowledge Math Practice Test

How do you calculate the area of a trapezoid?

1. 1/2 h(a + b)

2. bh

3. sum of lengths of sides

4. 2(3.14)(r)

The correct answer is: 1/2 h(a + b)

The area of a trapezoid is calculated using the formula 1/2 multiplied by the height (h) and the sum of the lengths of the two parallel sides (a and b). This formula effectively finds the average length of the two bases (a and b) and then multiplies that average length by the height to determine the area. In practical terms, a trapezoid has one pair of sides that are parallel, which we refer to as the bases. The height is the perpendicular distance between these two bases. By averaging the lengths of the bases, you create a representation of the trapezoid's width, and multiplying that by the height gives you the total area enclosed by the trapezoid. The other options provided do not relate to the calculation of the area of a trapezoid. For instance, bh represents the area of a rectangle, the sum of lengths of sides does not yield an area but gives a perimeter, and the formula related to 2(3.14)(r) pertains to the circumference of a circle, not a trapezoid. Thus, the selected formula is the accurate method for determining the area of a trapezoid.