When we connect a point on the circumference on a circle to the exact center, then the line segment made, is called as the radius of the circle.  The distance between the center of the circle to its circumference is the radius. The diameter is double the radius. Hence the formula is derived by dividing the diameter by 2.

The Radius Formula is given as,

$\large Radius\;of\;circle\:(r)=\frac{Diameter\:(d)}{2}$

Where,
r is the radius of the circle.
d is the diameter of the circle.

### Solved Examples

Question 1: Find the radius of the circle whose diameter is 19 cm ?
Solution:

Given,
Diameter of the circle = d = 14 cm

= $\frac{d}{2}$

= $\frac{19}{2}$ cm

= 9.2 cm

Question 2: Find the radius of the circle whose diameter is 30 cm ?
Solution:

Given,
Diameter of the circle = d = 25 cm

= $\frac{d}{2}$
= $\frac{30}{2}$ cm