Question

The center of a circle is at (4, -1) and it has a radius of 6. What is the equation of the circle?

Answer 1

`(x - 4)^2 + (y + 1 )^2 = 36`

Explanation:

The standard form of the equation of a circle is :

`(x - a )^2 + (y - b )^2 = r^2`

where (a , b ) is the coords of the centre and r , the radius.

here (a , b ) = (4 , -1 ) and r = 6

substitute these values into the standard equation

`rArr (x - 4 )^2 + (y + 1 )^2 = 36 " is the equation "`