1. Warm up 1.If you drew an angle on a piece of patty paper and were told to fold an angle bisector, how would you do it? 2.If you drew a segment on a piece of patty paper and were told to fold a perpendicular bisector, how would you do it?

2. 1.5 Special Points in Triangles 7 new vocab words

3. Inscribed Circle A circle INSIDE a triangle that touches just one point on each side. Incenter The center of an inscribed circle.

4. Circumscribed Circle A circle that is outside the triangle and touches all three vertices. circumcenter The center of a circumscribed circle. **Can be inside, outside or on the triangle.

5. Altitude A perpendicular line segment, from a vertex of a triangle to the opposite side.

6. Median A line segment from a vertex of a triangle to the opposite side, which cuts the side in half.

7. Perpendicular Bisector In a triangle, the perpendicular bisector DOES NOT have to start at a vertex. Double whammy

8. Folding triangles to create circumscribed & Inscribed circles You need: ♥straight edge ♥compass ♥Pencil ♥6 pieces of patty paper ♥patience

9. Folding perpendicular bisectors 1.Using your straight edge, draw a large triangle in the middle of one piece of patty paper. 2.FOLD perpendicular bisectors on each side (segment) of the triangle. 3.Trace over the folds with your pencil and straight edge. 4.What do you notice?

10. You have created the center to a circumscribed circle!!! Put the point of the compass on the CIRCUMCENTER and touch the pencil to a vertex…then another…. and another… just to make sure you have the right distance. Draw the circle. I find it easier to move the paper instead of the compass. Write this on your paper: I made a circumscribed circle using perpendicular bisectors.

11. folding angle bisectors 1.Using your straight edge and another piece of paper, draw a triangle. 2.Fold angle bisectors at each vertex. 3.Trace over them. 4.What do you notice?

12. You have created the center to an inscribed circle!!! Put the point of the compass on the INCENTER and touch the pencil to a side…then another…. and another… just to make sure you have the right distance. Draw the circle. I find it easier to move the paper instead of the compass. Write this on your paper: I made an inscribed circle using angle bisectors.

13. Your Assignment Wksht 1.5