Unit 1 Geometry Basics Review

Vocabulary practice flashcards covering Geometry Basics, including points, lines, planes, angles, and their related postulates and formulas.

Point

A location with no size or shape.

Line

Made up of points with no thickness or width.

Line Segment

A measurable part of a line consisting of two endpoints.

Ray

A line that extends indefinitely in one direction.

Plane

A flat surface made up of points and extends indefinitely in all directions.

Collinear

Points that lie on the same line.

Coplanar

Points that lie on the same plane.

Congruent Segments

If two segments have the same length, then they are congruent.

Segment Addition Postulate

If $A$, $B$, and $C$ are collinear points and $B$ is between $A$ and $C$, then $AB + BC = AC$.

Distance Formula

The formula used to find the distance between two points on a coordinate plane: $d = \sqrt{(x_2-x_1)^2+(y_2-x)^2}$.

Midpoint Formula

The formula used to find the midpoint between two endpoints: $M = (\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2})$.

Segment Bisector

A segment, line, or plane that intersects a segment at its midpoint.

Perpendicular

Two lines that intersect at a $90^{\circ}$ angle (right angle). Symbol: $L$.

Perpendicular Bisector

A line, segment, or ray perpendicular to a segment at its midpoint.

Parallel Lines

Two lines that never intersect. Symbol: $11$.

Angle

The intersection of two rays at an endpoint.

Vertex

The common endpoint of an angle (where the sides intersect).

Right Angle

An angle with a degree measure of $90^{\circ}$. Denotes $90^{\circ}$ angle.

Acute Angle

An angle with a degree measure less than $90^{\circ}$.

Obtuse Angle

An angle with a degree measure greater than $90^{\circ}$.

Straight Angle

An angle with a degree measure of $180^{\circ}$.

Congruent Angles

Two angles that have the same measure are congruent.

Adjacent Angles

Two angles that share a common side and vertex; "Next to" each other.

Angle Addition Postulate

If $\angle ABD$ and $\angle DBC$ are adjacent, then $\angle ABD + \angle DBC = \angle ABC$.

Angle Bisector

A line or ray that divides an angle into two equal parts.

Vertical Angles

Two angles directly across from each other on intersecting lines; always congruent.

Complementary Angles

Two angles with measures that sum to $90^{\circ}$ (do not have to be adjacent).

Supplementary Angles

Two angles with measures that sum to $180^{\circ}$ (do not have to be adjacent).

Linear Pair

Adjacent angles that are supplementary; combined, they form a straight line.