- A1386
- B2772
- C693
- D346.5
Step-by-Step Solution
Radius = 42 ÷ 2 = 21 m. A full circle would be ; a semicircle is half of that = . Forgetting to halve gives 1386; using 42 m as the radius gives 2772.
Answer: C) 693
A semicircular stage is built for a school function. Its straight edge (the diameter) measures 42 . Find the floor area of the stage. Use π = (answer in ).
Class 7Perimeter and AreaPerimeter and Area
Key idea: Area of a circle
**Area of a circle = π × .**
Note it's squared, not . So if , area = π × 49 (not π × 14).
Example cm, π = .
Example cm, π ≈ 3.14): A ≈ .
Note it's squared, not . So if , area = π × 49 (not π × 14).
Example cm, π = .
Example cm, π ≈ 3.14): A ≈ .
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