Question

The ratio of diameters of two circles is 5:6.Find the ratio of their circumferences.

Answer 1

let diameter of first circle, d₁= 5x units
diameter of second circle, d₂ = 6x units
radius of first circle, r₁ = (5x/2) units
radius of second circle, r_​2 = 3x units

$\frac{circumferenceoffirstcircle}{circumferenceofsecondcircle}=\frac{2{\mathrm{\pi r}}_1}{2{\mathrm{\pi r}}_2}=\frac{{\mathrm{r}}_1}{{\mathrm{r}}_2}=\frac{5x/2}{3x}=\frac{5}{6}$