(Q9).A joker’s cap is in the form of right circular cone whose base radius is 7 cm and height is 24 cm. Find the area of the sheet required to make 10 such caps.
Radius of the cap (r) = cm
Height of the cap (h) = cm
Slant height of the cap (l) = √(r2 + h2)
= √(2 + 2)
= √(+)
= √
=
∴ l = 25 cm.
Lateral surface area of the cap = Cone = πrl
L.S.A. = × × = cm 2.
∴ Area of the sheet required for 10 caps = × = cm2