Question

How do you write the equation of the circle with radius 9 and center (-2,3)?

Answer 1

`(x+2)^2+(y-3)^2=81`

Explanation:

The equation of a circle in standard form is.

`color(red)(|bar(ul(color(white)(a/a)color(black)((x-a)^2+(y-b)^2=r^2)color(white)(a/a)|)))`
where (a ,b) are the coordinates of the centre and r, the radius.

here a = -2 , b = 3 and r = 9

substitute these values into the standard equation.

`(x-(-2))^2+(y-3)^2=9^2`

`rArr(x+2)^2+(y-3)^2=81" is the equation of the circle"`