Angles are created by two distinct rays that share a common endpoint (also known as a vertex). ∠ ABC or ∠ B denote angles with vertex B.
Angle
Having the same size, shape and measure. Two figures are congruent if all of their corresponding measures are equal.
Congruent
Figures that have the same size and shape.
Congruent Figures
begins at a point and goes on forever in one direction.
Ray
A transformation that "flips" a figure over a line of reflection.
Reflection
An equation which states that two ratios are equal.
Proportion
Two lines are parallel if they lie in the same plane and they do not intersect.
Parallel Lines
The mapping, or movement, of all the points of a figure in a plane according to a common operation.
Transformation
A transformation that turns a figure about a fixed point through a given angle and a given direction.
Rotation
Comparison of two quantities by division and may be written as r/s, r:s, or r to s.
Ratio
A transformation that "slides" each point of a figure the same distance in the same direction.
Translation
One of the basic undefined terms of geometry. Traditionally thought of as having no length, width, or thickness, and often a dot is used to represent it.
Point
A line segment whose endpoints are the midpoint of two sides of a triangle is called a midsegment of a triangle.
Midsegment
One of the basic undefined terms of geometry. Traditionally thought of as a set of points that has no thickness but its length goes on forever in two opposite directions. AB denotes a line that passes through point A and B.
Line
Transformation that changes the size of a figure, but not the shape.
Dialation
Sides that have the same relative positions in geometric figures.
Corresponding Sides
Sides that have the same relative positions in geometric figures.
Corresponding Sides
divides a segment or angle into two equal parts.
Bisector
The part of a line between two points on the line. AB denotes a line segment between the points A and B.
Line Segame to
An equation which states that two ratios are equal.
Proportion