Geometry Vocabulary Point an exact location in space Line A straight path that goes on forever in both directions A and B are any 2 points on the line. B

Ray A straight path that goes on forever in one direction Plane A flat surface that goes on forever in all directions A straight path that has two endpoints Line segment plane ABC Starts at A and goes through B

Intersecting lines Lines that cross at one point Perpendicular lines Lines that cross at right angles Parallel lines Lines (in a plane ) that never cross

Angle Angles is formed when 2 lines or rays intersect Vertex the point where the 2 lines or rays intersect in an angle N B A C

Acute angle an angle whose measure is less than 90 degrees Obtuse angle an angle whose measure is between 90 and 180 degrees Straight angle an angle whose measure is exactly 180 degrees

Right angle an angle whose measure is exactly 90 degrees Complementary angles Two angles whose measures add up to 90 degrees Supplementary angles Two angles whose measures add up to 180 degrees

Vertical angles Two angles across from each other when 2 lines cross They are always congruent! Adjacent angles Two angles next to each other They share a side and a vertex