Mensurationmedium · Past Paper
The total surface area of a right circular cone is 90π sq. cm. If its radius is 5 cm, find its slant height.
A18 cm
B13 cm
C9 cm
D12 cm
✓ Correct Answer: B — 13 cm
πr(l + r) = 90π. 5(l + 5) = 90. l + 5 = 18. l = 13 cm.
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