MathematicsA piece of paper is in the shape of a semicircular region of radius 10 cm . It is rolled to form a right circular cone. The slant height is:

A piece of paper is in the shape of a semicircular region of radius $10 cm$ . It is rolled to form a right circular cone. The slant height is:

A
10 cm
B
20 cm
C
15 cm
D
5 cm

Solution:

Given that a piece of paper is in the shape of a semicircular region of radius 10 cm.
Piece of paper is in shape of semi-circular of radius 10cm and its transformation into right circular cone is given below,

When we convert a semi-circle into a cone then radius of semi-circle becomes equal to slant height of cone.
The radius of the semi-circle will be equal to the slant height of the cone.
Therefore, slant height is 10 cm.
Therefore, the correct answer is option (1).