Geometry Proof Terms

Two lines in the same plane that will never intersect

• Parallel Lines

• Skew Lines

• Perpendicular Lines

• Line Segment

Part of a line beginning from an endpoint and then continuing forever.

• Ray

• Line

• Line Segment

• Straight Angle

Part of a line consisting of two endpoints and all points in between them.

• Ray

• Line

• Line Segment

• Straight Angle

A straight path that has no thickness and extends forever.

• Ray

• Line

• Plane

• Line Segment

A triangle with one 90 degree right angle.

• Acute Triangle

• Right Triangle

• Obtuse Triangle

• Equilateral Triangle

Two or more lines that share a common point of intersection.

• Parallel Lines

• Intersecting Lines

• Ray

• Line Segment

Two lines that intersect at 90 degree angles.

• Parallel Lines

• Skew Lines

• Perpendicular Lines

• Line Segment

A triangle with three congruent sides

• Equilateral Triangle

• Isosceles Triangle

• Scalene Triangle

• Right Triangle

A triangle with two congruent sides

• Equilateral Triangle

• Isosceles Triangle

• Scalene Triangle

• Right Triangle

A triangle with no congruent sides

• Equilateral Triangle

• Isosceles Triangle

• Scalene Triangle

• Right Triangle