2020 · Q77
Suppose a region is formed by removing a sector of 20° from a circular region of radius 30 feet. What is the area of this new region?
Elementary MathematicsMensuration
- A150π square feet
- B550π square feet
- C650π square feet
- D850π square feet
Explanation
Removing a 20° sector leaves 340/360 of the disc: (340/360) × π × 30² = 850π cm². The full disc has area π × 30² = 900π cm². Removing the 20° sector leaves 17/18 × 900π = 850π cm².