Geometry Concepts

1. Geometry Concepts Introduction Point, Line, Ray, Angles

2. Def: location in space Label with capital letter Def: set of points extending infinitely in both directions Label two points on the line AB Point Line Point D B D A

3. C B A Plane • Def: a flat surface extending endlessly in all directions plane BAC

4. Def: part of a line with two endpoints Label the two endpoints Def: part of a line, one endpoint, extends infinitely in one direction Label endpoint and one other point AB CD Ray Line Segment D A C B

5. HIS S I H vertex SIH Angle • Def: two rays with a common endpoint, called the vertex • Label and name in three ways S H I

6. o o o = 90 90 90 and o = 180 o 180 Acute: Right: Straight: Obtuse:

7. o o o 50 40 45 Def: the sum of the measures of two angles = 90 Def: the sum of the measures of two angles = 180 o o o 135 Complementary angles: Supplementary angles: + +

8. Def: two lines in the same plane that never intersect B D G F A AB CD EF GH E C H Parallel Lines PerpendicularLines Def: two lines that intersect to form right angles

9. Def: Two lines that cross at a common point F 1 G 4 P 3 EF GH 1 2 4 3 2 E H intersects at point P Intersecting Lines Vertical Angles Def: Opposite pairs of congruent angles formed by intersecting lines

10. o 360 180 and o ReflexAngle

11. 1 and 2 are adjacent angles 1 2 AdjacentAngles Def: two angles with a common vertex and a common side but no common interior points

12. Phew!!! That’s all, folks.