What is the equation of the circle with a center at #(-4 ,2 )# and a radius of #7 #?

2 Answers
Apr 18, 2018

The equation you're looking for is #(x+4)^2+(y-2)^2=7^2#.

Explanation:

The standard equation for a circle is as follows:

#(x-h)^2+(y-k)^2=r^2#

where h and k are the x and y coordinates of the circle's centre, respectively, and r is the radius of the circle.

In your problem, your h value is negative, so the two negatives cancel out and make a positive 4.

Apr 18, 2018

#(x+4)^2+(y-2)^2=49#

Explanation:

#"the equation of a circle in standard form is"#

#color(red)(bar(ul(|color(white)(2/2)color(black)((x-a)^2+(y-b)^2=r^2)color(white)(2/2)|)))#

#"where "(a,b)"are the coordinates of the centre and r"#
#"is the radius"#

#"here "(a,b)=(-4,2)" and "r=7#

#rArr(x-(-4))^2+(y-2)^2=7^2#

#rArr(x+4)^2+(y-2)^2=49larrcolor(red)"equation of circle"#