The trapezoid area formula adds the two parallel bases, multiplies by the height, then takes half. So the feeder skills are adding, multiplying, and halving a number (multiplying by 1/2). Warm these up and the formula is just three clean steps.
Answer these 3, then press Show my path. No grade — this just points you to the right level.
1. What is 7 + 5?
2. What is half of 12?
3. What is 6 × 8?
A trapezoid has two parallel sides called bases. To find its area you add the two bases, multiply by the height, then take half. Halving is the same as multiplying by 1/2 or dividing by 2.
Your quick check picks one for you, but you can switch any time:
Level 0 Practice halving and adding, one step at a time.
A. What is half of 8?
Half of 8 means 8 ÷ 2 = 4.
B. What is 5 + 3?
5 + 3 = 8.
C. What is half of 16?
16 ÷ 2 = 8.
Level 1 Combine the steps the trapezoid formula uses.
A. Add the two bases: 7 + 9 = ___?
7 + 9 = 16.
B. Now multiply that sum by a height of 2: 16 × 2 = ___?
16 × 2 = 32.
C. Take half of 32 to finish: ___?
Half of 32 = 32 ÷ 2 = 16 square units.
Level 2 Stretch through the whole trapezoid idea.
A. Bases are 5 and 7, height is 4. First add the bases: 5 + 7 = ___?
5 + 7 = 12.
B. Multiply by the height (4) then halve: half of (12 × 4) = ___?
12 × 4 = 48, then half of 48 = 24 square units.
1. What is half of 18?
18 ÷ 2 = 9.
2. Add the bases 8 and 6, then take half: ___?
8 + 6 = 14, then half of 14 = 7.
You've practiced exactly what Lesson 5-2 uses. Time to dive in.
Start Lesson 5-2 →