Worked examples
Two examples
Example 1
An L-shaped room is a 12 ft by 10 ft rectangle with a 4 ft by 3 ft corner missing. What is its area?
- The whole rectangle: 12 × 10 = 120.
- Take away the missing corner: 4 × 3 = 12. 120 − 12.
Answer: 108 square feet
Example 2
A window is a 4 ft wide, 5 ft tall rectangle with a half circle on top. Use 3.14. What is its area?
- The rectangle: 4 × 5 = 20.
- The half circle has a radius of 2 (half the width): 3.14 × 22 = 12.56, and half of that is 6.28.
- Add the pieces: 20 + 6.28.
Answer: 26.28 square feet
Where this is taught: Quiz 27: Perimeter and Area, “A room that is not a rectangle”
The drill
Ten problems
How many:
Type each answer, then press Check my answers at the bottom. Commas in large numbers are fine.Write each answer on the line. The answer key, with the reasoning, is on the last page.