Question

if area of quadrant of circle is 38.5 find diameter​

Answer 1

the diameter is 1.4 as the d is 2x the radius

Answer 2

$area \: of \: circle = \pi {r}^{2} \: \: \: where \: r \: is \: radius \: of \: circle \\ area \: of \: quadrant = \frac{\pi {r}^{2} }{4} \\ 38.5 = \frac{1}{4} \times \frac{22}{7} \times {r}^{2} \\ \frac{385 \times 4 \times 7}{10 \times 22} = {r}^{2} \\ {r}^{2} = \frac{35 \times 4 \times 7}{10 \times 2} \\ {r}^{2} = 7 \times 7 \\ r = 7 \: units \\ diameter = 2r \\ = 2 \times 7 \\ = 14 \: units$

diameter of circle is 14 units