Question

A $7m$ wide road runs outside around a circular park, whose circumference is $176m$. The area of the road is: $(Use\pi =\frac{22}{7})$

Answer 1

Radius of the park $=r$

Circumference of the park $=2\pi r$

$176=2\pi r$

$r=\frac{176}{2\pi }$

$r=\frac{176}{2\times \frac{22}{7}}$

$r=\frac{176\times 7}{2\times 22}$

$r=28m$

Area of road $=\pi (28+7{)}^2-\pi (28{)}^2$

$=\pi ({35}^2-{28}^2)$

$=\frac{22}{7}(35-28)(35+28)$

$=\frac{22}{7}\times 7\times 63$

$=1386m^2$