2021 · Q23
A sector is cut from a circle of radius 21 cm. If the length of the arc of the sector is 55 cm, then what is the area of the sector?
Elementary MathematicsCircles
- A577.5 cm²
- B612.5 cm²
- C705.5 cm²
- D725.5 cm²
Explanation
A sector's area equals half the product of radius and arc length: (1/2)*r*l. With r = 21 cm and arc length 55 cm, the area is 0.5*21*55 = 577.5 cm^2. This is the sector-area analogue of (1/2)*base*height for a triangle. Hence option (a).