Correct Answer:
B. 308 cm²
To find the curved surface area of a hemisphere, we use the formula for half the surface area of a full sphere. The surface area of a sphere is 4πr², so the curved surface area of a hemisphere is 2πr². Given the radius (r) is 7 cm, the calculation is 2 × (22/7) × 7 × 7 = 2 × 22 × 7 = 44 × 7 = 308 square centimeters (B).
- 154 cm² (A) is the area of the flat circular base of the hemisphere (πr²).
- 616 cm² (C) is the total surface area of a full sphere with a radius of 7 cm (4πr²).
- 77 cm² (D) does not correspond to any standard surface area calculation for a hemisphere or sphere with radius 7 cm.