Question

the ratio of the diameter of 2 circles is 3:7 what is the ratio of their circumferences

Answer 1

Diameter = 2(radius)
Let diameters of circles be d1 and d2
Radii of the circles be r1 and r2
Given d1/d2 = 3/7 therefore r1/r2=2(3)/2(7) =3/7
Circumference = 2πr
Ratio of circumferences =2πr1/2πr2
=> r1/r2 =3/7

Hope it helps

Answer 2

the ratio of diametee of 2 circle is 3:7.
circumference of circle is 2πr.
C1:C2=2×22/7×1.5:2×22/7×3.5.
=9.42:22