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

2 Answers
charredwind
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.

Jim G.
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"

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