Question

If the diameter of the wheel is $0.5$ meters, then the radius of the wheel is how many centimeters?

Answer 1

Find the radius of the wheel:

It is given that the diameter of the wheel is $0.5$ meters.

Since the diameter is twice the radius. Thus,

$\begin{array}{rcl}\mathrm{diameter}& =& 2\times \mathrm{radius}\end{array}$

Substitute, $\begin{array}{rcl}\mathrm{diameter}& =& 0.5\mathrm{meters}\end{array}$ into the above equation:
$\begin{array}{rcl}& \Rightarrow & 0.5\mathrm{meters}=2\times \mathrm{radius}\\ & \Rightarrow & \mathrm{radius}=\frac{0.5\mathrm{meters}}{2}\\ & \Rightarrow & \mathrm{radius}=0.25\mathrm{meters}\\ & \Rightarrow & \mathrm{radius}=0.25\times 100\mathrm{cm}\left[\therefore 1\mathrm{m}=100\mathrm{cm}\right]\\ & \Rightarrow & \mathrm{radius}=25\mathrm{cm}\end{array}$

Hence, the radius is $25\mathrm{cm}$.