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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

quadrilateral

a four sided polygon

parallelogram

a quadrilateral with two pair of parallel sides

regular polygon

a polygon with congruent sides and angles

square

a rectangle with four congruent sides

vertical angle

a pair of opposite congruent angles formed by intersecting lines