Question

The given figure shows a solid formed of a solid cube of side 40 cm and a solid cylinder of radius 20 cm and height 50 cm attached to the cube as shown.

Find the volume and the total surface area of the whole solid. [Take π = 3.14].

Answer 1

Edge of a cube = I = 40 cm

∴ Volume of a cube = I³ = (40)³ = 64000 cm³

Radius of a solid cylinder = r = 20 cm

Height of a solid cylinder = h = 50 cm

∴ Volume of cylinder = πr²h

= 3.14 × 20 × 20 × 50

= 62800 cm³ 

∴ Volume of whole solid = Volume of cube + Volume of cylinder

= (64000 + 62800) cm³ 

= 126800 cm³ 

Total surface area of the whole solid

= Total surface area of a cube + Curved surface area of a cylinder

= 6l² + 2πrh

= 6 × (40)² + 2 × 3.14 × 20 × 50

= 6 × 1600 + 6280

= 9600 + 6280

= 15880 cm²