A rectangular strip 25 cm× 7 cm is rotated about the longer side. Find the total surface area of the solid thus generated.

Question

A rectangular strip 25 cm&#xD7; 7 cm is rotated about the longer side. Find the total surface area of the solid thus generated.

Philoid · Accepted Answer

Given,

Dimension of rectangular strip = 25 cm × 7cm

When this strip is rotated about its longer side :

So,

Height of cylinder thus form = 25 cm

Radius = 7 cm

∴ Total surface area of cylinder =