31 terms

# Geometry

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point
names a location
line
perfectly straight surface and extends forever in both directions
plane
a perfectly flat surface and extends forever in all directions.
segment
part of a line between two points
ray
part of a line that starts at one point and extends forever in one direction.
angle
formed by two rays with a common endpoint called a vertex.
right angle
measures 90 degrees
acute angle
measures less than 90 degrees
obtuse angle
greater than 90 degrees yet less than 180 degrees
complementary angles
have measures that add to 90 degrees
supplementary angles
have measures that add up to 180 degrees.
conguent
have the same shape and size
parallel lines
lines in a plane that never meet
perpendicular lines
lines that intersect at 90 degrees
transversal
line that intersects two or more lines that lie in the same plane
Triangle sum theory
angle measures of a triangle in a plane add to 180 degrees
acute triangle
has 3 acute angles
right triangle
has 1 right angle
obtuse triangle
1 obtuse angle
equilateral triangle
has 3 congruent sides and angles
iscosceles triangle
has at least two congruent sides and angles
scalene triangle
has no congruent sides or angles
polygon
a closed plane figure formed by three or more segments.
rhombus
a parallelogram with all sides congruent
trapezoid
polygon with one pair of parallel sides
rectangle
a parallelogram with four right angles