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Example 9.39 from Prealgebra, 9.4 Use Properties of Rectangles, Triangles, and Trapezoids
Use Properties of Rectangles, Triangles, and Trapezoids: example 9.39
Find the area of a trapezoid whose height is feet and whose bases are and feet.
Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.
Solution
Step 1. Read the problem. Draw the figure and label it with the given information. Step 2. Identify what you are looking for. the area of the trapezoid Step 3. Name. Choose a variable to represent it. Let A = the area Step 4.Translate.
Write the appropriate formula.
Substitute.Step 5. Solve the equation. Step 6. Check: Is this answer reasonable?
The area of the trapezoid should be less than the area of a rectangle with base 13.7 and height 5, but more than the area of a rectangle with base 10.3 and height 5.
Step 7. Answer the question. The area of the trapezoid is 60 square feet.
Your turn
The book's Try It right after this example: same idea, new numbers. Only the answer is given.
The height of a trapezoid is centimeters and the bases are and centimeters. What is the area?
How did it go?