9th Grade Mathematics Summative Reviewer

Vocabulary flashcards covering fundamental geometry terms, postulates, parallel line relationships, and linear function concepts including slope and zeros.

Point

The most basic element of geometry that represents a specific location in space and is completely zero-dimensional with no size, width, length, or depth.

Line

A straight path of points that extends forever in two opposite directions and is one-dimensional, containing an infinite number of points.

Undefined Terms

Terms that do not exist but can only be described, used to define other terms in geometry; specifically Point, Line, and Plane.

Line Segment

A measurable part of a line with a fixed length that has two distinct boundaries called endpoints.

Ray

A part of a line that has one endpoint and extends infinitely in only one direction.

Plane

A flat, two-dimensional surface extending infinitely in all directions that has length and width but no thickness.

Angle

A geometric figure formed when two rays share the same endpoint called a vertex.

Vertex

The shared endpoint where the two rays (sides) of an angle meet.

Collinear points

Points that lie on the same line.

Coplanar points

Points that lie on the same plane.

Transversal

In a plane, a line that intersects two or more lines, each at a different point.

Interior

The region between the two lines that are cut by a transversal.

Exterior

The two regions not located between the lines that are cut by a transversal.

Alternate Interior Angles (AIA)

Pairs of angles located inside the lines and on opposite sides of the transversal that are congruent when the lines are parallel.

Same Side Interior Angles (SSI)

Pairs of angles located inside the lines and on the same side of the transversal that are supplementary ($180^{\circ}$) when the lines are parallel.

Slope ($m$)

A measure of the steepness and directional trend of a line, calculated as the rate of change: $m = \frac{\Delta y}{\Delta x} = \frac{y_2 - y_1}{x_2 - x_1}$.

Zero of a Function

The specific input value ($x$) that yields an output ($y$) of exactly zero, representing the $x$-intercept on a geometric graph.

Rise

The vertical displacement required to travel between two points on a graph; upward movement is positive and downward is negative.

Run

The horizontal displacement between two points on a graph; rightward movement is positive and leftward is negative.

Slope-Intercept Form

A linear equation form written as $y = mx + b$, where $m$ is the slope and $b$ is the y-intercept.

Standard Form

A linear equation form written as $Ax + By = C$, where the slope is calculated using the formula $m = -\frac{A}{B}$.

Line Postulate

A geometric rule stating that for any two points, there is exactly one line that contains both points.

Plane Intersection Postulate

A geometric rule stating that if two planes intersect, then their intersection is a line.