Question

The number 3.14 is a rounded value of the mathematical quantity π. If you replace 3.14 with π, what is the exact formula for the circumference in terms of the diameter, d, and in terms of the radius, r?

Answer 1

Circumference of a circle is given by:

where

C represents the circumference of a circle.

r represents the radius of a circle.

As per the statement:

Use and diameter(d) = 2r units

Circumference in terms of diameter (d) is:

Substitute the value of we have;

units

Now:

find the circumference in terms of radius r.

units

Therefore, the exact formula for the circumference in terms of the diameter, d is, C = 3.14d and in terms of r is C= 6.28r.

Answer 2

Formula for the circumference in terms of the diameter, d = πd

Formula for the circumference in terms of the radius, r = 2πr