The radius and height of a solid right circular cone is 8 cm and 15 cm. The total surface area of the cone:-
Answer & explanation
Correct answer: option 3
l= slant height
l = \(\sqrt {r^2 + h^2 }\) = \(\sqrt {8^2 + 15^2}\)
= \(\sqrt {64 + 225}\) = \(\sqrt {289}\) = 17 cm
Now,
C.S.A. = \(\pi \)rl
Area of base = \(\pi \)r2
T.S.A. = C.S.A. + area of base
= \(\pi \)rl + \(\pi \)r2
= \(\pi \)r (l + r)
= \(\frac{22}{7}\) × 8 × 25
= \(\frac{4400}{7}\)
= 628.5 cm2