Unit 5 Flashcards
acute angle
an angle measuring less than 90° but greater than 0°
angle
A figure created by two distinct rays that share a common endpoint (also known as a vertex).
angle of rotation
The amount of rotation (in degrees) of a figure about a fixed point such as the origin.
bisector
A point, line or line segment that divides a segment or angle into two equal parts.
circle
The set of all points equidistant from a point in a plane.
congruent
Having the same size, shape and measure.
corresponding angles
Angles that have the same relative position in geometric figures.
corresponding sides
Sides that have the same relative position in geometric figures
endpoint
The point at each end of a line segment or at the beginning of a ray.
image
The result of a transformation.
intersection
The point at which two or more lines intersect or cross.
isometry
a distance preserving map of a geometric figure to another location using a reflection, rotation or translation.
line
One of the undefined terms of geometry that represents an infinite set of points with no thickness and its length continues in two opposite directions indefinitely
line segment
A part of a line between two points on the line
line of symmetry
a line separating a figure into two halves that are mirror images.
line symmetry
exists for a figure if for every point on one side of the line of symmetry, there is a corresponding point the same distance from the line
obtuse angle
an angle measuring greater than 90° but less than 180°
parallel lines
Two lines are parallel if they lie in the same plane and do not intersect.
perpendicular lines
Two lines are perpendicular if they intersect to form right angles.
point
One of the basic undefined terms of geometry that represents a location.
pre-image
A figure before a transformation has taken place.
ray
A part of a line that begins at a point and continues forever in one direction
reflection
A transformation of a figure that creates a mirror image, “flips,” over a line.
line of reflection
A line that acts as a mirror so that corresponding points are the same distance from the mirror.
rotation
A transformation that turns a figure about a fixed point through a given angle and a given direction, such as 90° clockwise.
regular polygon
a two-dimensional figure with all sides and all angles congruent
right angle
an angle measuring 90˚
transformation
The mapping, or movement, of all points of a figure in a plane according to a common operation, such as translation, reflection or rotation.
translation:
A transformation that slides each point of a figure the same distance in the same direction.
vertex
The location at which two lines, line segments or rays intersect.
