1. MID-TERM STUFF
HONORS GEOMETRY

2. Theorem Polygon Angle Sum Theorem
The sum of the measures of the angles in a polygon
is (n – 2)180.
Find the sum of the measure of the angles of a 15-gon.

3. Theorem: Polygon Angle-Sum Theorem
The sum of one set of exterior angles for any polygon is 360°. 1 5 2 4 3
m<1 + m<2 + m<3 + m<4 + m<5 = 360°

4. Definitions
Concurrent lines: three or more lines intersect in the same point.
Point of concurrency: the point of intersection of the lines.

5. Definition of a Median
A median is a segment from a vertex of a triangle to the midpoint of its opposite side.

6. Definition of a Centroid
The centroid is the point of concurrency of the medians.

7. THEOREM

8. How does CM related to HC?
Find
HC =

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

10. PERPENDICULAR BISECTORS
A perpendicular bisector of a triangle: It is a line (ray or segment) that is perpendicular to the side of a triangle at its midpoint.

11. Isosceles Triangle Vertex Angle Leg Leg Base Angle Base Base Angle
Base angles of an Isosceles triangle are congruent &
the legs of an Isosceles Triangle are congruent

12. The bisector of the vertex angle of an isosceles triangle is the median, altitude & perpendicular bisector. midpoint.