NCERT Exemplar Solutions
Class 10 - Mathematics - CHAPTER 12: Surface Areas & Volumes - Exercise 12.1
Question 19

Question. 19

In a right circular cone, the cross-section made by a plane parallel to the base is a

(A)

circle

(B)

frustum of a cone

(C)

sphere

(D)

hemisphere

Step 1: A right circular cone has a circular base and a pointed top (vertex).

Step 2: The base of the cone is a circle. Now imagine a flat surface (a plane) cutting the cone, but this plane is kept parallel to the base.

Step 3: When the cutting plane is parallel to the base, the shape of the cut (cross-section) will be the same shape as the base.

Step 4: Since the base is a circle, the cross-section is also a circle.

Final Answer: The cross-section is a circle (Option A).