Question

A right circular cone has a radius of 7 cm and a height of 24 cm. Find the area of the sheet required to make 7 such cones.

(a) 3846.5 cm^2

(b) 1052 cm^2

(c) 1153.4 cm^2

(d) 3172 cm^2

This question was addressed to me in my homework.

My enquiry is from Surface Area and Volume of Different Solid Shapes topic in portion Surface Area and Volumes of Mathematics – Class 10

Answer 1

The correct choice is (a) 3846.5 cm^2

Best explanation: Slant height = \(\sqrt {h^2+r^2}\)

= \(\sqrt {24^2+7^2}\)

= \(\sqrt {576+49}\)

= 25 cm

Area required to make 7 such cones = 7 × Lateral surface area of a right circular cone

= 7 × (πrl)

= 7 × 3.14 × 7 × 25

= 3846.5 cm^2