Question

The ratio of the circumference of a circle to its diameter is _______ .

• A. equal to r
• B. equal to 2r
• C. equal to $r^2$
• D. independent of r

Answer 1

The correct option is D independent of r

Let us consider a circle of radius r.
Its diameter (d) = 2 x radius = 2r and
circumference = 2$\pi$r

So, $\frac{Circumference}{Diameter}$ = $\frac{2\pi r}{2r}$ = $\pi$

Hence, the ratio of the circumference of any circle to its diameter is equal to $\pi$, which is a constant and does not depend on the radius of the circle.