A portion of a line that begins at one endpoint and extends without end in one direction only

Back

Rigid Motion

Front

Preserves distance and angle measures

Back

Altitude of a Triangle

Front

The perpendicular segment from a vertex of a triangle to the opposite side or to the line that contains the opposite side

Back

Equilateral Triangle

Front

Has three equal sides, each of the angles measures 60°

Back

Reflection

Front

An isometry that flips the figure over a line

Back

Plane

Front

A flat surface that extends without end in all directions;
infinite number of connected lines in a flat surface; 2D

Back

Supplementary Angles

Front

Two angles whose measures have a sum of 180 degrees

Back

Alternate Exterior Angles

Front

Two non-adjacent exterior angles on opposite sides of the transversal; if transversal intersects parallel lines they are congruent

Back

Transformation

Front

The moving of a figure by a translation (slide), rotation (turn) or reflection (flip)

Back

Right Triangle

Front

A triangle with one right angle

Back

Isometry

Front

Transformation that preserves lengths, angle measures, parallel lines, and distances between points

Back

Perpendicular

Front

Lines that intersect at right angles

Back

Dilation

Front

A transformation that changes the size of an object, but not the shape; not an isometry

Back

Image

Front

The figure you get after a transformation

Back

Acute Triangle

Front

A triangle with all acute angles

Back

Angle

Front

A figure formed by two rays with a common endpoint called the vertex

Back

Scalene Triangle

Front

A triangle with no congruent sides

Back

Congruent

Front

Having the same size and shape

Back

Vertical Angles

Front

Angles that are formed by two intersecting lines but are NOT adjacent; measures are congruent

Back

Linear Pair

Front

Two angles that are adjacent to each other and are supplementary

Back

Compositions of Transformations

Front

Multiple transformations performed on an image

Back

Radius

Front

A segment whose endpoints are the center and any point on the circle.

Back

Translation

Front

An isometry that "slides" each point of a figure the same distance in the same direction; (x+a, y+b)

Back

Equidistant

Front

Same distance from a point of line as another point or line.

Back

Alternate Interior Angles

Front

Two non-adjacent interior angles on opposite sides of the transversal; if transversal intersects parallel lines they are congruent

Back

Isosceles Triangle

Front

A triangle in which at least two sides have the same length

Back

Point

Front

A specific location in space that has no size or shape; named with a capital letter

Back

Skew

Front

Lines that do not intersect and are not coplanar

Back

Concurrent

Front

A point where three or more lines intersect at one point

Back

Midpoint

Front

The point that is halfway between the endpoints of the line segment

Back

Adjacent Angles

Front

Angles that share a common side and vertex

Back

Coplanar

Front

Points and lines that lie in the same plane

Back

Line Segment

Front

Two points and all of the points on the line connecting them, named by its two endpoints

Back

Collinear

Front

Points that lie on the same line

Back

Polygon

Front

A closed plane figure formed by three or more line segments

Back

Obtuse Triangle

Front

A triangle with one obtuse angle

Back

Line

Front

A straight object that is infinitely long and infinitely thin; a straight path that extends without end in opposite directions; in coordinate geometry y = mx + b

Back

Equal

Front

Having the same numerical value

Back

Complementary Angles

Front

Two angles whose measures have a sum of 90 degrees

Back

Preimage

Front

In a transformation, it is the original figure.

Back

Triangle

Front

Consists of three straight side whose three angles always add up to 180°

Back

Similarity

Front

Two polygons are similar if and only if their corresponding angles are equal and their corresponding sides are proportional.

Back

Opposite Ray

Front

Two rays that have a common endpoint and form a line

Back

Segment Bisector

Front

A ray, line, segment, or plane that divides a segment into two parts of equal measure

Back

Rotation

Front

An isometry that turns a figure about a fixed point

Back

Mapping of a Transformation

Front

The pairing of every point in a preimage with a point in an image

Back

Median of a Triangle

Front

Segment from a vertex to the midpoint of the opposite side

Back

Corresponding Angles

Front

Lie on the same side of the transversal and in corresponding positions; if transversal intersects parallel lines they are congruent

Back

Central Angle

Front

Of a regular polygon is an angle formed by radii drawn to two consecutive vertices

Back

Perpendicular Bisector

Front

A ray, line, segment, or plane that is perpendicular to a segment at its midpoint

Back

Section 2

(13 cards)

Construction

Front

A geometric drawing created using only a compass and a straight edge

Back

Parallelogram

Front

Opposite sides are parallel and congruent; opposite angles are congruent; consecutive angles are supplementary; diagonals bisect each other

Back

Exterior Angle

Front

An angle outside the polygon formed by a side and an extension of an adjacent side

Back

Incenter

Front

The point of concurrency of the three angle bisectors of a triangle

Back

Triangle Inequality Theorem

Front

The sum of the lengths of ANY two sides of a triangle must be greater than the length of the third side

Back

Parallel Lines

Front

Two lines that are in the same plane, but do not intersect, have the same slope

Back

Circumcenter of a Triangle

Front

The point of concurrency of the perpendicular bisectors of the three sides of a triangle

Back

Trapezoid

Front

A quadrilateral with exactly one pair of parallel sides

Back

Transversal

Front

A line that intersects two coplanar lines

Back

Rhombus

Front

A parallelogram with four congruent sides; diagonals are perpendicular; diagonals bisect base angles

Back

Interior Angle

Front

Formed by two sides of a polygon, the sum of the angles in degrees of any polygon is 180(n-2) where n is the number of sides

Back

Rectangle

Front

A parallelogram with four right angles; congruent diagonals

Back

Square

Front

All the properties of a parallelogram, rhombus, and rectangle