Module 15: Lesson 4 Perpendicular Bisectors of Triangles Vocabulary The triangle is circumscribed by the circle. The triangle is inscribed by the circle. A Think of the words Circumnavigate and inside. B C

3 or more lines that intersect at the same point are said to be concurrent. The point of intersection is called the point of concurrency. The point of concurrency for 3 perpendicular bisectors of a triangle is called the circumcenter (Point G). Circumcenter Theorem The perpendicular bisectors of the sides of a triangle intersect at a point that equidistant from the vertices of the triangle.

If OF = 7, OB = 25, and AD = 20 Find AO and AC If AO = 85, OF = 13, and AC = 136 Find CD and BO If CO = 65, AE = 63, and EO = 16 Find AB and BO If FO = 25, AO = 65, and BC = 120 Find CF and CO

Find the circumcenter of the triangle with vertices R (-6, 0), S (0, 4), O (0, 0) Graph the triangle. Find the equation for 2 perpendicular bisectors. Graph the 2 perpendicular bisectors and find the intersection which is the circumcenter.

Homework pages 772-775 #’s 5-12, 15 (all)