Question

Areas of some circles are given below find their diameters.
(a) 176 sq cm (b) 394.24 sq cm

Answer 1

Area of a circle is given by the formula

$A=\pi r^2$

$a)176=\pi r^2$

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

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

$8\times 7=r^2$

$2\sqrt{14}cm=r$

Diameter $=2r=4\sqrt{14}cm$

$b)394.24=\frac{22}{7}{r}^2$

$\frac{394.24\times 7}{22}=r^2$

$17.92\times 7=r^2$

$125.44=r^2$

$\sqrt{125.44}=r$

$11.2=r$

Diameter $=2r=2\times 11.2=22.4$ cm