How would you find the equation of the circle, center at (5,-3) and radius of 4?

1 Answer
Mar 4, 2018

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

Explanation:

the eqn of a circle with centre (a,b) radius r

is given by

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

in this case we have

centre (5,-3), radius" "r=4

eqn

(x- 5)^2+(y- -3)^2=4^2

=>(x- 5)^2+(y+3)^2=4^2

expanding

x^2-10x+25+y^2+6y+9=16

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