Question

The inside circumference of a circular track is 440 m long and the track is 7 m wide everywhere. The area of the track is

• A. $3200m^2$
• B. $3234m^2$
• C. $3571m^2$
• D. $2800m^2$

Answer 1

The correct option is B $3234m^2$

$2\pi r=440\Rightarrow r=70m.$, outer radius $=70+7=77$
Area of track $=\pi (R^2-r^2)$
$\pi (70+77)(77-70)=\frac{22}{7}\times 147\times 7=22\times 147=3234$