Question

12 concrete cylindrical pillars of a building are to be covered by aluminum
cladding. Each pillar has a diameter of 70 cm and height of 7m.
1. How much concrete is needed to construct the concrete pillars?

Answer 1

$\text{The required volume }V\text{ of concrete is}$

$V=n*V_c\text{ where}$

$n=12\text{ number of columns } V_c \text{ volume of one column}$

$\text{according to the right cylinder volume formula }$

$V_c=\pi*r^2*h;\ h=7m;\ r=\frac{0.7}{2}=0.35m$

$V_c=\pi*0.35^2*7\approx2.69m^3$

$V= 12*2.69=32.28m^3$

Answer: $V=32.28m^3$ required amount of concrete