Mensurationmedium · Past Paper
The total surface area of a right circular cone is 90π cm². If its radius is 5 cm, find its slant height.
A13 cm
B12 cm
C15 cm
D10 cm
✓ Correct Answer: A — 13 cm
πr(r+l) = 90π => 5(5+l) = 90 => 5+l = 18 => l = 13 cm.
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