Recall that the circle contains all point which are radius away from its center.
Graph:
Equation:
(x-4)^2+(y-2)^2=9
Practice makes perfect
We want to sketch a graph of a circle with 3 unit long radius and center in ( 4, 2) and write its equation in a graphing form. Let's start by graphing it. To do so, we should connect all points which are 3 units away from the given center.
Next, let's recall the graphing form of the equation of a circle.
(x- h)^2 + (y- k)^2 = r^2
In the equation above, point ( h, k) is the center and r is the radius of the circle. In our case, we were told that ( 4, 2) is the center and 3 is the radius, which allows us to write its equation.
(x- 4)^2 &+ (y- 2)^2 = 3^2
& ⇕
(x-4)^2&+(y-2)^2=9
