Basic Terms in Geometry

The common endpoint of the two rays of the angle

• point

• line

• rays

• vertex

It is formed by two noncollinear rays with a common endpoint.

• line

• angle

• plane

• circle

Two lines that intersect and formed a right angles.

• Intersecting lines

• Perpendicular lines

• Parallel lines

• Skew lines

An angle with measure equal to 90°

• Acute angle

• Complementary angle

• Straight angle

• Right angle

An angle with measure equal to 180°

• Straight angle

• Supplementary angle

• Linear pair

• Obtuse angle

An angle with measure between 0° and 90°

• Acute angle

• Complementary angle

• Right angle

• Adjacent angle

one dimensional and extends without end in two directions

• Plane

• Line

• Line segment

• Ray

What does this image show?

• intersecting lines

• perpendicular lines

• right angle

• parallel lines

Points that lie on the same line

• Coplanar points

• Noncollinear points

• Collinear points

• Noncoplanar points

Points that lie in the same plane

• Coplanar points

• Collinear points

• Noncollinear points

• Noncoplana points