Question

In a cylinder,radius is doubled and height is halved.The curved surface area will be: (a) halved (b) doubled (c) same (d) four times

Answer 1

(c) it remains same
explaination

c.s.a of cylinder = 2*pie*r*h

c.s.a of cylinder = 2 * 22/7 * 2r * h/2

c.s.a of cylinder = 2* 22/7 * r * h

c.s.a of cylinder = 2*pie * r* h

Answer 2

Answer:-

★ Consider:-

Let the radius of a cylinder = r unit

Let the height of a cylinder = h unit.

★ According to question,

Radius is doubled = 2r

Height is halved = h/2

★ Then,

Curved surface area of a cylinder = 2 × π × r × h

Curved surface area = 2 × π × 2 × r × h/2

= 2 × π × r × h

This is same as the curved surface area of the cylinder with radius r and height h.

Hence, option C is the correct answer.