00:01
We're given the diameter endpoints being negative 1, 2, 117.
00:05
So we need to use those points to find the center of the circle, find the radius of the circle, so we can write the equation of the circle.
00:14
So to find the center, we're going to use the midpoint formula, which is x1 plus x2 divided by 2, y1 plus y2 divided by 2.
00:25
So we label x1, y1, x2, y2, so we replace.
00:32
Get negative 1 plus 11 divided by 2, and we get 2 plus 7 divided by 2.
00:38
This reduces to 5, and this stays 9 over 2.
00:42
So that is our hk, or our center, in our equation.
00:48
So now we're going to find the distance using the endpoints of the diameter.
00:53
So this distance, our d, is our diameter.
00:56
So at the end, we're going to have to divide it by 2.
00:59
So the equation for the distance formula is x2 minus x1 squared plus y2 minus y1 square...