7. If the radius of base of a cylinder is doubledand the height remain

1.	7. If the radius of base of a cylinder is doubledand the height remains unchanged, its curvedsurface arca becomes:three timesdoublede halfno change
Answer» Let old radius = r1 New radius = r2 = 2r1 —(1) Height of both (reduced and original cylinder) = h Similarly CSA of cylinder = 2πrh Therefore, ratio of reduced to original cylinder area= r1/r2 =r1/(2r1) = 1/2

7. If the radius of base of a cylinder is doubledand the height remains unchanged, its curvedsurface arca becomes:three timesdoublede halfno change

Answer»

Let old radius = r1

New radius = r2 = 2r1 —(1)

Height of both (reduced and original cylinder) = h

Similarly CSA of cylinder = 2πrh

Therefore, ratio of reduced to original cylinder area= r1/r2

=r1/(2r1) = 1/2