Question 388029: Find the radius of the circle defined by the equation: x^2+y^2-10x+4y+4=0. Found 2 solutions by ewatrrr, MathLover1:Answer by ewatrrr(24785) (Show Source):
Hi,
Standard Form of an Equation of a Circle is
where Pt(h,k) is the center and r is the radius
x^2+y^2-10x+4y+4=0
completing the squares to put into the standard form
x^2 -10x + y^2 +4y + 4 = 0
(x-5)^2 -25 + (y +2)^2 - 4 + 4 = 0
(x-5)^2 + (y+2)^2 = 25
Center is (5,-2) radius = 5
You can put this solution on YOUR website! Recall the equation of a circle:
where (h,k) is the circle's center and is the radius.
In this problem, we need to complete the square to get the equation in the above form.
.......you just need to realize that you take half of the linear term (x and y)
..................>....
It's obvious from above that the center of the circle is (5,-2) and radius is .
