Example 5
Writethe equationof the circlein the graph.Fromthe graphwe can see that the centerof the circleis at point and the radiusis unitslong.Thusthe equationis:Example 6
Determineif the pointis on the circlegivenby the equation:
In orderto find the answer, we simplyplug the point into the equationof the circle.The point satisfiesthe equationof the circle.Example 7
Find the equationof the circlewhosediameterextendsfrom pointto
The generalequationof a circleis: