What is the ratio of the circumference of a circle to its radius?

What is the ratio of the circumference of a circle to its radius?

دائرے کے فریم کا اس کے رداس کا تناسب کیا ہے؟
Explanation

As we all know

Circumference of the circle: 2πr

The radius of the circle: r

Ratio = 2πr : r = 2πr/r = 2π

Thus we conclude that 2π:1