Question

What is the radius of a circle whose equation is -10xt6y+18-0?

O 2 units
O 4 units
O8 units
O 16 units

Answer 1

Radius, r = 4 units

Explanation:

The equation of circle is given by :

`x^2+y^2-10x+6y+18=0`

We need to find the radius of the circle.

The general equation of a circle is given by :

`(x-h)^2+(y-k)^2=r^2` ....(1)

We can rearrange the above equation in terms of the given equation as follows :

`x^2+y^2-10x+6y+18-25-9+25+9=0\\\\(x^2-10x+25)+(y^2+6y+9)+18-25-9=0\\\\(x-5)^2+(y-(-3))^2=(4)^2`

On comparing the above equation with equation (1)

h = 5, k = -3 and r = 4

So, the radius of the circle is 4 units.