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
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Alternate Exterior Angles
Front
Two non-adjacent exterior angles on opposite sides of the transversal; if transversal intersects parallel lines they are congruent
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Transformation
Front
The moving of a figure by a translation (slide), rotation (turn) or reflection (flip)
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Right Triangle
Front
A triangle with one right angle
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Isometry
Front
Transformation that preserves lengths, angle measures, parallel lines, and distances between points
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Perpendicular
Front
Lines that intersect at right angles
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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
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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
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Congruent
Front
Having the same size and shape
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Vertical Angles
Front
Angles that are formed by two intersecting lines but are NOT adjacent; measures are congruent
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Linear Pair
Front
Two angles that are adjacent to each other and are supplementary
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Compositions of Transformations
Front
Multiple transformations performed on an image
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Radius
Front
A segment whose endpoints are the center and any point on the circle.
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Translation
Front
An isometry that "slides" each point of a figure the same distance in the same direction; (x+a, y+b)
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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
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Isosceles Triangle
Front
A triangle in which at least two sides have the same length
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Point
Front
A specific location in space that has no size or shape; named with a capital letter
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Skew
Front
Lines that do not intersect and are not coplanar
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Concurrent
Front
A point where three or more lines intersect at one point
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Midpoint
Front
The point that is halfway between the endpoints of the line segment
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Adjacent Angles
Front
Angles that share a common side and vertex
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Coplanar
Front
Points and lines that lie in the same plane
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Line Segment
Front
Two points and all of the points on the line connecting them, named by its two endpoints
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Collinear
Front
Points that lie on the same line
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Polygon
Front
A closed plane figure formed by three or more line segments
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Obtuse Triangle
Front
A triangle with one obtuse angle
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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
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Equal
Front
Having the same numerical value
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Complementary Angles
Front
Two angles whose measures have a sum of 90 degrees
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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.
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Opposite Ray
Front
Two rays that have a common endpoint and form a line
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Segment Bisector
Front
A ray, line, segment, or plane that divides a segment into two parts of equal measure
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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
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Median of a Triangle
Front
Segment from a vertex to the midpoint of the opposite side
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Corresponding Angles
Front
Lie on the same side of the transversal and in corresponding positions; if transversal intersects parallel lines they are congruent
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Central Angle
Front
Of a regular polygon is an angle formed by radii drawn to two consecutive vertices
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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
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Parallelogram
Front
Opposite sides are parallel and congruent; opposite angles are congruent; consecutive angles are supplementary; diagonals bisect each other
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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
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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
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Trapezoid
Front
A quadrilateral with exactly one pair of parallel sides
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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