Mensurationhard · Past Paper
The radius and height of a cone are in the ratio 3:4. If its curved surface area is 188.4 cm², find its radius (Take π = 3.14).
A3 cm
B6 cm
C9 cm
D12 cm
✓ Correct Answer: B — 6 cm
r=3x, h=4x, so l=5x. CSA = πrl = 3.14 * 3x * 5x = 47.1x² = 188.4 => x² = 4 => x = 2. r = 3 * 2 = 6 cm.
Share this question
More from Mensuration
- A triangular prism has a base perimeter of 24 cm and lateral surface area of 240 cm². Find its height.
- What happens to the volume of a cylinder if its radius is halved and its height is doubled?
- The total surface area of a right circular cone is 90π cm². If its radius is 5 cm, find its slant height.
- If the volume of a sphere is numerically equal to its surface area, find its diameter.
- A cylinder has radius 'r' and height '2r'. A sphere has radius 'r'. What is the ratio of their volumes?