acute angle

an angle under 90 degrees

acute triangle

a triangle with all acute angles

angle

2 rays that share a common endpoint

central angle

angle that has the center of a circle its vertex

chord

a line segment that connects 2 points on a circle

circle

a set of points in a plane equidistant from a point called the origin or the center

complementary angles

2 angles that complete a right angle

congruent

having the same measure

diagonal

a line segment that connects 2 points not already connected

diameter

a chord that goes through the origin

equilateral triangle

a triangle that has all sides congruent

isosceles triangle

a triangle that has 2 sides congruent

scalene triangle

a triangle that has no sides congruent

kite

a quadrilateral with a pair of pairs of adjacent congruent sides

line

1-D a straight path that extends infinetly in opposite directions

line segment

a part of a line or ray that extends between 2 endpoints

obtuse angle

an angle over 90 degrees

obtuse triangle

a triangle with at least 1 angle over 90 degrees

parallel lines

lines that are on the same plane and never intersect

parallelogram

a quadrilateral with a pair of pairs of parallel lines

perpendicular lines

lines that intersect at a right angle

plane

2-D, 3 points can name it and it extends infinetly in all directions

point

0-D, an exact location in space

polygon

a closed figure made of three or more line segments

radius

1/2 of a diameter

ray

has 1 endpoint and extends infinetly in the other direction

rectangle

an equiangular figure

reflection

when a figure flips across the line of reflection

regular

equilateral and equiangular

rhombus

a parallelogram,quadrilateral with all sides congruent

right angle

angle at exactly 90 degrees

right triangle

a triangle with one right angle

rotation

when a figure turns around a fixed point

sector

wedge shape created by the central angle

skew lines

non collinear lines that don't intersect

square

equilateral and equiangular polygon

straight angle

a 180 degree angle

supplementary angles

supply a straight angle

transversal lines

intersect parallel lines

trapezoid

1 paip of parallel sides

vertex

a common endpoint for 2 line segments or rays or angles etc.

vertical angles

formed by two intersecting lines and are congruent