Question

Find the radius of the circle whose equation is x^2 + y^2 = 4.

Answer 1

The radius is 2

EXPLANATION

The given equation of the circle is

`{x}^(2) + {y}^(2) = 4`

.This is the same as

`{x}^(2) + {y}^(2) = {2}^(2)`

We campare to the equation of the circle with center at the origin.

`{x}^(2) + {y}^(2) = {r}^(2)`

We have

`r = 2`

.Hence the radius of the circle is 2

Answer 2

Radius of the given circle is r = 2.

Explanation:

Given equation of the circle is
`x^2 + y^2 = 4`.

Now we need to find the radius of the given circle
`x^2 + y^2 = 4`.

To find that let's compare with the formula of the circle with is
`x^2 + y^2 = r^2`, where r is the radius.

We get
`r^2 = 4`

take square root of both sides.

`r=2`

Hence radius of the given circle is r = 2.