Question

The volume of material required to construct 7 cylindrical pillars having a circular base of radius 40 cm and of height 20 m = m${}^3$.

• A. 7040
• B. 70.4
• C. 704
• D. 7.04

Answer 1

The correct option is B 70.4

Radius of the cylinder = 40 cm
Height of the cylinder = 20m = 2000 cm
Volume of one cylinder is

$=\pi r^{2}h=\frac{22}{7}\times 40\times 40\times 2000$
$=\frac{70400000}{7}c{m}^3$
$1cm={10}^{-2}m$
$1c{m}^3={10}^{-6}{m}^3$
$\therefore 70400000c{m}^3=70.4m^3$
Thus, volume of 7 such pillars $=\frac{70.4}{7}\times 7=70.4m^3$