F. is a radiusof the circle.Inscribedand CircumscribedPolygons
A convexpolygonwhoseverticesall toucha circleis said to be aninscribedpolygon.A convexpolygon
whosesidesall toucha circleis said to be acircumscribedpolygon.The figuresbelowshowexamples
of inscribedand circumscribedpolygons.
Equationsand Graphsof Circles
A circleis definedas the set of all pointsthat are the samedistancefrom a singlepointcalledthecenter.
This definitioncan be usedto find an equationof a circlein the coordinateplane.
Let’s considerthe circleshownbelow. As you can see, this circlehas its centerat point and it has a
radiusof.
All the points on the circleare a distanceof unitsawayfrom the centerof the circle.
We can expressthis informationas an equationwith the help of the PythagoreanTheorem.The right triangle
shownin the figurehas legs of length and and hypotenuseof length. We write:
We can generalizethis equationfor a circlewith centerat point( , ) and radius.