Question

From a circle of radius 12 cm, a sector of 45 degrees is cut and made into a cone. Find the volume of the cone so obtained.

Answer 1

Answer:

The length of arc is given as=

360

x

×2πr

360

120

×2×π×12

3

1

2π×12

2π×4

8π

This become the circumference of base circle= 2πr=8π

2r=8

r=4

According to Pytagorous theorm

(Slantheight)

2

=(height)

2

+(radius)

2

12

2

=(height)

2

+4

2

144=(height)

2

+16

(height)

2

=144−16

(height)

2

=132

height=

132

Volume of cone=

3

1

πr

2

h

3

1

×

7

22

×4×4×

132

21

362

132