# What is the equation of a circle whose center is at the origin and whose radius is 16?

**Solution:**

Given center of circle is origin and radius is 16 units

We know that equation of a circle with radius r and centre (h,k) is

(x - h)^{2} + (y - k)^{2} = r^{2}

Here, centre is origin hence, h = 0 and k = 0, r = 16

⇒ (x - 0)^{2 }+ (y - 0)^{2 }= 16^{2}

⇒ x^{2 }+ y^{2} = 256

The equation of the circle is x^{2 }+ y^{2 }= 256.

## What is the equation of a circle whose center is at the origin and whose radius is 16?

**Summary:**

The equation of a circle whose center is at the origin and whose radius is 16 is x^{2 }+ y^{2 }= 256.