Question
Find the area of the metal sheet required to make two closed hollow cones each of height 24 cm and slant height 25 cm.
Solution
h = 24 cm l = 25 cm
l2 = r2 + h2
⇒ (25)2 = r2 + (24)2 ⇒ r = 7 cm
∴ Area of the metal sheet required = 2(rl)
= 600 cm2