Question

Radius of circle
x² + y² =4 ?​

Answer 1

Answer:

The general equation of a circle is:

(

x

−

a

)

2

+

(

y

−

b

)

2

=

r

2

Where

(

a

,

b

)

represent the coordinates of the center and

r

is the radius.

Here in the equation:

x

2

+

y

2

=

4

(

x

−

0

)

2

+

(

y

−

0

)

2

=

2

2

Therefore, the circle has :

center

(

0

,

0

)

Radius

r

=

2

Answer 2

Answer:

Given

x

2

+

y

2

=

r

2

→

x

2

+

y

2

=

4

Subtract

x

2

from both sides giving:

y

2

=

4

−

x

2

Take the square root of both sides

y

=

√

4

−

x

2

Now write it as

y

=

±

√

4

−

x

2