Question

The central angle and radius of a sector of a circular disc are 180°and 21cm respectively .If the edges of the sector are joined together to make a hollow cone,then find the radius of the cone.​

Answer 1

Step-by-step explanation:

The cone is being created by joining the radius. So the radius of the sector is going to be the slant height of the cone.

Slant height (L)=21 cm

Arc length of the sector = Circumference of the base of the cone

Length of arc =

360

θ

×2πR

Here R represents radius of the sector

=

360

180

×2×

7

22

×21

=

2

1

×2×22×3

=66 cm

So, circumference of the base of the cone =66

2πr=66

2×

7

22

×r=66

r=66×

2

1

×

22

7

r=10.5 cm

Radius of the cone =10.5 cm

Hence, this is the answer.

solution

hope it will help you