ACT Math : How to find the area of a trapezoid
Study concepts, example questions & explanations for ACT Math
All ACT Math Resources
Example Questions
Example Question #1 : How To Find The Area Of A Trapezoid
What is the area of this regular trapezoid?
45
26
20
32
32
To solve this question, you must divide the trapezoid into a rectangle and two right triangles. Using the Pythagorean Theorem, you would calculate the height of the triangle which is 4. The dimensions of the rectangle are 5 and 4, hence the area will be 20. The base of the triangle is 3 and the height of the triangle is 4. The area of one triangle is 6. Hence the total area will be 20+6+6=32. If you forget to split the shape into a rectangle and TWO triangles, or if you add the dimensions of the trapezoid, you could arrive at 26 as your answer.
Example Question #1 : How To Find The Area Of A Trapezoid
What is the area of the trapezoid above if a = 2, b = 6, and h = 4?
24
32
64
16
8
16
Area of a Trapezoid = ½(a+b)*h
= ½ (2+6) * 4
= ½ (8) * 4
= 4 * 4 = 16
Example Question #1 : How To Find The Area Of A Trapezoid
Find the area of a trapezoid if the height is 
Write the formula to find the area of a trapezoid.
Substitute the givens and evaluate the area.
Example Question #1 : How To Find The Area Of A Trapezoid
Trapezoid 
The formula for the area of a trapezoid is:
We have here the height and one of the bases, plus the area, and we are being asked to find the length of base 
Thus,
Example Question #1 : How To Find The Area Of A Trapezoid
Find the area of a trapezoid given bases of length 6 and 7 and height of 2.
To solve, simply use the formula for the area of a trapezoid.
Substitute
into the area formula.
Thus,
All ACT Math Resources
