This document discusses secondary parts of triangles including angle bisectors, perpendicular bisectors, medians, and altitudes. It defines each part and notes that angle bisectors meet at the incenter, perpendicular bisectors meet at the circumcenter, medians meet at the centroid, and altitudes meet at the orthocenter. Diagrams are included showing how to draw triangles inside and outside of circles.

2. SECONDARY PARTSOF A TRIANGLE E-Math pp.132-136

3. Can YOU do this? Figure 1 Draw a circle. Then draw a triangle inside it whose vertices are on the circle. Figure 2 Draw a circle. Then draw a triangle outside it, making sure the circle is touching the triangle.

4. How about THIS? Figure 3 Draw the figure in the right, this time drawing the triangle first. Figure 4 Draw the figure in the right, this time drawing the triangle first.

5. Secondary Parts of a Triangle: Angle Bisectors Perpendicular Bisectors Medians Altitudes

6. Angle Bisector a segment that bisects an angle of the triangle; endpoints are a vertex and a point on opposite side

7. Perpendicular Bisector a line that passes through the midpoint of a side of the triangle, and is perpendicular to it

8. Median a segment connecting a vertex of a triangle and the midpoint of the opposite side

9. Altitude a segment from the vertex of the triangle perpendicular to the line containing the opposite side

10. Points of Concurrency Angle Bisectors INCENTER Perpendicular Bisectors  CIRCUMCENTER Medians  CENTROID Altitudes  ORTHOCENTER