The height of a right circular cylinder is 10/5 m. Three times the sum

1.	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» We have, Height of cylinder = 10.5 m 3(A+A) = 2 curved surface area (where, A= circular area of box) 3×2A = 2(2πrh) 6A = 4πrh 6πr² = 4πrh r²/r = 4πh/6π r = 2/3 h = 2×10.5 / 3 = 7m ∴ Volume of cylinder = πr²h = 22/7 × 7 × 7 × 10.5 = 1617 m³

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»

We have,

Height of cylinder = 10.5 m

3(A+A) = 2 curved surface area (where, A= circular area of box)

3×2A = 2(2πrh)

6A = 4πrh

6πr² = 4πrh

r²/r = 4πh/6π

r = 2/3 h

= 2×10.5 / 3

= 7m

∴ Volume of cylinder = πr²h

= 22/7 × 7 × 7 × 10.5

= 1617 m³