ABC26GN4947 · Volume and Surface Area
Subject: General Aptitude · Chapter: Volume and Surface Area · Exam: · Marks: · Difficulty:
The slant height of a right circular cone is 10 m and its height is 8 m . Find the area of its curved surface.
(a)$30 \pi \mathrm{m}^{2}$
(b)$40 \pi \mathrm{m}^{2}$
(c)$60 \pi \mathrm{m}^{2}$
(d)$80 \pi \mathrm{m}^{2}$
Answer
Explanation
$l=10 \mathrm{m}, h=8 \mathrm{m}$. So, $r=\sqrt{l^{2}-h^{2}}=\sqrt{(10)^{2}-8^{2}}=6 \mathrm{m}$. $$\text { ∴ } \text { Curved surface area }=\pi r l=(\pi \times 6 \times 10) \mathrm{m}^{2}=60 \pi \mathrm{m}^{2} .$$
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