| A | B |
|---|
point,  | a single, exact location represented by a dot |
decagon,  | a polygon with ten sides and angles |
line segment,  | a straight path from one point to another |
intersecting lines,  | two or more lines that meet at a point |
parallel lines,  | two lines that lie in the same plane and do not intersect |
perpendicular lines,  | two lines that intersect at right angles |
ray,  | part of a line, having only one endpoint |
vertex,  | the point that rays have in common |
| acute angles, | angles that measure less than 90° |
obtuse angles,  | angles that measure more than 90° but less than 180° |
right angles,  | angles that measure exactly 90° |
straight angles,  | angles that measure exactly 180° |
adjacent angles,  | two angles that sit directly next to each other |
vertical angles,  | two angles that sit directly across from each other |
reflex angle,  | an angle that measures between 180° and 360° |
congruent,  | having the same size and shape |
equilateral triangle,  | a triangle with three congruent angles and sides |
isosceles triangle,  | a triangle with two congruent angles and sides |
scalene triangle,  | a triangle with no congruent sides or angles |
polygon,  | a two-dimensional figure that is made up of three or more line segments joined end to end to make one closed path |
regular polygon,  | a polygon whose sides are all the same length and interior angles are all the same |
concave polygon,  | a polygon where at least one vertex is “pushed in” |
convex polygon,  | a polygon in which all vertices are “pushed out” |
quadrangle,  | a polygon with four sides; also called a quadrilateral |
quadrilateral,  | a polygon with four sides |
parallelogram,  | a quadrilateral with two pairs of parallel sides |
rectangle,  | a parallelogram with four right angles |
square,  | a rectangle whose sides are all the same length |
pentagon,  | a polygon with five sides and angles |
hexagon,  | a polygon with six sides and angles |
heptagon,  | a polygon with seven sides and angles |
octagon,  | a polygon with eight sides and angles |
nonagon,  | a polygon with nine sides and angles |
line,  | a straight path that is endless in both directions |
