Mathematics 9: Basic Geometry and Functions

Vocabulary-style flashcards covering basic geometry undefined terms, line subsets, angle pairs formed by transversals, and the fundamentals of relations and functions.

Point

A location in space that has no size (no length, width, or height), represented by a dot and named using a capital letter.

Line

A straight path that extends infinitely in both directions, has no endpoints, and is named using two points on it.

Plane

A flat surface that extends infinitely in all directions, has length and width but no thickness, and is named using 3 points.

Line Segment

A part of a line with two endpoints and a fixed length.

Ray

A part of a line with one endpoint that extends infinitely in one direction.

Angle

Formed when two rays meet at a common endpoint called the vertex; measured in degrees ($^\text{o}$).

Vertex

The common endpoint where two rays meet to form an angle.

Perpendicular Lines

Two lines that meet at a $90^\text{o}$ angle.

Parallel Lines

Lines that never meet and are always the same distance apart.

Transversal

A line that cuts through two or more lines.

Adjacent Angles

Angles that share a common side and vertex.

Vertical Angles

Opposite angles formed by intersecting lines that are always equal.

Complementary Angles

Two angles whose sum is $90^\text{o}$.

Supplementary Angles

Two angles whose sum is $180^\text{o}$.

Corresponding Angles

Angles in the same position on different intersections; they are equal if lines are parallel.

Alternate Interior Angles

Angles inside the two lines on opposite sides of the transversal; they are equal if lines are parallel.

Alternate Exterior Angles

Angles outside the two lines on opposite sides of the transversal; they are equal if lines are parallel.

Same-side Interior Angles

Angles inside the lines on the same side of the transversal with a sum of $180^\text{o}$.

Ordered Pairs

A pair written as $(x, y)$ where $x$ is the input and $y$ is the output.

Table of Values

An organized list of input ($x$) and output ($y$) used to find patterns.

Mapping Diagram

A visual showing how $x$-values connect to $y$-values using arrows to show the relationship.

Graph

A plot of ordered pairs on a coordinate plane that shows a relationship visually.

Relation

Any set of ordered pairs.

Function

A relation where each $x$-value has only one $y$-value.