Question

The height of a right circular cylinder is 10.5 m. Three times the sum of the areas of its two circular faces is twice the area of the curved surface. Find the volume of the cylinder.

Answer 1

Given, Height of right circular cylinder = 10.5 m

And 3(area of both circular ends) = 2(curved surface area of cylinder)

= 3\(\times\)πr² = 2\(\times\)2πrh = 6πr² = 4πrh

= 3r = 2h

or  r = \(\cfrac23\)h = \(\cfrac23\times10.5\) = 7 m

So, volume of cylinder = πr²h = \(\cfrac{22}7\times \) 49 \(\times\) 10.5

= 1617 m³