Basic Geometry Terms

Front

Part of a line with two endpoints

Back

Line segment

Front

Point that bisects a segment

Back

Midpoint

Front

Angle between 90° and 180°

Back

Obtuse angle

Front

Two-dimensional, extends without end

Back

Plane

Front

No dimension, represented by a dot

Back

Point

Front

Part of a line with an endpoint extending in one direction

Back

Ray

Front

Angle measure: 90°

Back

Right angle

Front

Angle measure: 180°

Back

Straight angle

Front

Two angles that sum to 180°

Back

Supplementary angles

Front

Two angles with opposite rays

Back

Vertical angles