Answer:
10 cm
Explanation:
Given:
A circular piece of paper of a radius of 20 cm is cut in half and each half is made into a hollow cone by joining the straight edges.
To find:
Find the slant height and base radius of each cone.
Solution:
The radius of the circular piece of paper = 20 cm
Finding the slant height of each cone:
Since the straight edges of the semi-circular part is joined together to form a cone
∴ Slant height of the cone so formed = Radius of the circular piece = 20 cm
Thus, the slant height of the cone is → 20 cm.
Finding the base radius of each cone:
Let "r" cm be the base radius of each cone.
We have,
[Length of the base of each cone] = [Length of each semi-circular part of the original circular piece of paper]
⇒
2
�
�
=
2
�
×
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
�
2
2πr=
2
2π × radius of original circle
⇒
2
�
=
2
×
20
2
2r=
2
2×20
⇒
2
�
=
20
2r=20
⇒
�
=
10
�
�
r=10cm
Thus, the base radius of each cone is → 10 cm.