Question

If the area of quadrant of a circle is 38.5 cm^2 the the diametre is

Answer 1

$area \: of \: quadrant = \frac{1}{4} \pi \: {r}^{2} \\ 38.5 \times 4= 3.14 \times {r}^{2} \\ {r}^{2} = \frac{38.5 \times 4}{3.14} \\ {r}^{2} = \frac{154}{3.14} = \frac{15400}{314} ≈ 50 \\ r = 5 \sqrt{2} \\ Diameter = 2r = 2(5 \sqrt{2} ) = 10 \sqrt{2}cm$