Question

a joker cap is in the form of a right circular cone of base radius 7 cm and height 27 cm find the area of the sheet required to make 10 such caps

Answer 1

r = 7cm
h = 27cm

l = √r² + h²
= √49+27²
= √49+729
= 27.8cm

C.S.A of one cone = πrl
= 22/7 × 7 × 27.8
= 22×27.8
= 611.6cm²

Sheet required for 10 such cones = area of one cone × 10
= 611.6 × 10
= 6116cm²

Answer 2

Solution:

Given radius = 7 cm

Given height = 24 cm

To find:

The Curved Surface Area of Cone -

We know that;

=> πrl

Let's find the value of 'l' at first;

Since,

=> l = √r^2 + h^2

=> l = √7^2 + 24^2

=> l = √49 + 576

=> l = √625

=> l = √25^2

Hence, => l = 25 cm

Now,

=> πrl

=> 22/7 × 7 × 25

=> 22 × 25

=> 550 cm^2

Also, area of sheet required to make 10 such caps;

=> 550 × 10

=> 5500 cm^2