Question

The diameter of a cylinder is \[28\] cm and its height is \[20\] cm. Find the volume of the cylinder?

Answer 1

Hint:
Here we use the concept of volume of 3D Figures. Find the unknown value by assigning the values in the formula.
Required Formulae:
$\begin{array}{l}
{V_{cylinder}} = \pi {r^2}h\\
d = 2 \times r
\end{array}$

Complete step by step solution:
The diameter of a cylinder is 28 cm and its height is 20 cm.
According to the question, $d = 2r = 28cm$
$ \Rightarrow r = \dfrac{{28}}{2} = 14cm$
$h = 20cm$
$V = \pi \times 14 \times 14 \times 20$
     $\begin{array}{l}
 = \pi \times 196 \times 20\\
 = 3920 \times \pi \\
 = 3920 \times \dfrac{{22}}{7}\\
 = 12320\\
\therefore {V_{cylinder}} = 12320c{m^3}
\end{array}$

Note:
In such types of questions which involves the concept of 3D figures having knowledge of terms related to figures and related formulae is needed. Apply the values to the terms in the formula and solve for the unknown.