Unit 1 Euclidean Geometry Vocabulary

Fundamental Geometric Concepts and Spatial Relationships

• Point: A location that has zero ($0$) dimensions.

• Segment: Part of a line with two ($2$) endpoints.

• Distance: The length of a path between two ($2$) points.

• Collinear: Describes points that are "Together on a line".

• Coplanar: Describes objects or points that are "Together on a plane".

Bisection and Midpoints

• Midpoint: A point that divides a segment into two ($2$) congruent segments.

• Bisector: The line that divides something into two ($2$) equal parts.

• Perpendicular Bisector: A segment, ray, line, or plane that is perpendicular to a segment at its midpoint.

Classifications of Angles and Congruence

• Acute: Description of an angle whose measure is strictly less than $90^\circ$.

• Right Angle: An angle that measures exactly $90^\circ$.

• Obtuse: Description of an angle whose measure is strictly greater than $90^\circ$.

• Congruent: Describes two segments or angles that have the exact same measure.

Geometric Angle Pairs and Relationships

• Adjacent Angle: Angles that have the same vertex, share a common side, and do not overlap.

• Vertical Angle: A pair of opposite congruent angles formed by intersecting lines.

• Complementary: Describes two angles whose sum equals $90^\circ$.

• Supplementary: Describes two angles whose sum equals $180^\circ$.

• Linear Pair: Two angles that share a common side whose sum equals $180^\circ$.