College Math Placement Practice Test

What is the area of a trapezoid with bases of 4 and 8, and a height of 5?

1. 20

2. 30

3. 40

4. 50

The correct answer is: 30

To calculate the area of a trapezoid, you can use the formula: \[ \text{Area} = \frac{1}{2} \times (b_1 + b_2) \times h \] where \( b_1 \) and \( b_2 \) are the lengths of the two bases, and \( h \) is the height. In this case, the lengths of the bases are 4 and 8, and the height is 5. Plugging these values into the formula gives: \[ \text{Area} = \frac{1}{2} \times (4 + 8) \times 5 \] First, calculate the sum of the bases: \[ 4 + 8 = 12 \] Next, multiply this sum by the height, which is 5: \[ 12 \times 5 = 60 \] Now, take half of that product: \[ \text{Area} = \frac{1}{2} \times 60 = 30 \] Thus, the area of the trapezoid is 30. This confirms that the correct answer is indeed the one provided. The calculations