A race track is in the form of a rig whose inner circumference is 352 m and outer circumference is 396 m.
A race track is in the form of a rig whose inner circumference is 352 m and outer circumference is 396 m. Find the width and the area of the track.
Let r m and R m be the radii of the inner and outer tracks.
Now,
Circumference of the outer track $=2 \pi R$
$\Rightarrow 396=2 \times \frac{22}{7} \times R$
$\Rightarrow R=\frac{396 \times 7}{44}$
$\Rightarrow R=63$
Circumference of the inner track $=2 \pi r$
$\Rightarrow 352=2 \times \frac{22}{7} \times r$
$\Rightarrow r=\frac{352 \times 7}{44}$
$\Rightarrow r=56$
Width of the track = Radius of the outer track - Radius of the inner track
$=63-56$
$=7 \mathrm{~m}$
Area of the outer circle $=\pi R^{2}$
$=\frac{22}{7} \times 63 \times 63$
$=12474 \mathrm{~m}^{2}$
Area of the inner circle $=\pi R^{2}$
$=\frac{22}{7} \times 56 \times 56$
$=9856 \mathrm{~m}^{2}$
Area of the track $=12474-9856$
$=2618 \mathrm{~m}^{2}$