40 terms

# Geometry terms

Terms for the Algebra/Geometry Midterm
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Point
An exact location
Plane
A flat surface extending in 2 directions without end (name using 3 NON-colinear points)
Space
The set of all points
Line
Points extending in opposite directions without end
Segment
A portion of a line between 2 end points
Ray
A portion of a line with 1 endpoint that extends in 1 direction to infinity
Angle
The intersection of 2 rays
Acute angle
An angle whose measure is less than 90 degrees
Right angle
An angle whose measure equals 90 degrees
Obtuse angle
An angle whose measure is between 90 and 180 degrees
Straight angle
An angle whose measure equals 180 degrees
Collinear
Means points on the same line
Complementary angles
Two angles whose sum is 90 degrees
Supplementary angles
Two angles, of whose sum is 180 degrees
Coplanar
Points in the same plane
Rectangle
a parallelogram with all four sides forming right angles
Midpoint
Point in the middle of a segment
Opposite rays
Rays that are going in opposite directions and share the endpoint
Parallel
Lines in the plane that do not intersect.
Perpendicular
Lines that intersect forming right angles
Skew lines
Lines that are in different planes that do not intersect
Acute triangle
A triangle in which all the angles are less than 90 degrees
Scalene triangle
A triangle with none of the sides being congruent
Isosceles triangle
A triangle with at least 2 that are congruent
Equilateral triangle
A triangle with equal sides
Circle
The set of all points in a plain equal distance from a center point
Congruent
Equal distance
Regular polygon
A polygon with all the angles and sides being congruent
Major arch
An arch whose measure is more than 180 degrees
Semicircle
An arch whose measure equals 180 degrees
Parallelogram
A quadrilateral whose opposite sides are both parallel
Rhombus
A parallelogram with all 4 sides being congruent and forming right angles
Trapezoid
A quadrilateral with 1 pair of opposite sides being parallel
Similar
When a figure is an enlargement or reduction of a original figure
Isometry
When the pre-image and the final image are congruent
Dilation
A similarity transformation (can be a enlargement or a reduction)
Translation
The "shift" of a figure over parallel lines of reflection (orientation is the same)
Rotation
The reflection of a figure over 2 intersecting lines (orientation is the same)
Glide Reflection
The reflection of a figure over at least 3 intersecting lines
Tessellation
A repeated geometric pattern that covers a plane