Question

Is area of a circle proportional to square of its radius? What is the constant of proportionality?​

Answer 1

So the area of a circle is proportional to R2 and pi is the constant of proportionality between the area and the radius of a circle. The volume of a sphere is given by 4/3pi R2 so the volume goes as the cube (third power) of the radius and 4/3pi is the constant of proportionality.

Answer 2

y = kx for some non-zero constant k. The constant k is called the constant of proportionalitystep