an angle that measures less than 90o | Acute Angle |
angles that share a common side | Adjacent Angles |
interior angles of a transversal with the same measure | Alternate Interior Angles |
exterior angles of a transversal with the same measure | Alternate Exterior Angles |
formed when two rays have the same endpoint | Angle |
the sum of adjacent angles equals 90o | Complementary Angles |
angles with the same measure | Congruent Angles |
Angles that are in the same position (matchers) on a transversal | Corresponding Angles |
an angle that measures greater than 90o | Obtuse Angle |
angles that are across from each other - usually congruent | Opposite Angles |
a device that is used to measure an angle | Protractor |
an angle that measures 90o | Right Angle |
one of the rays that form an angle | Side |
an angle measuring 180o | Straight Angle |
the sum of adjacent angles equals 180o | Supplementary Angles |
The point where two rays meet to form an angle | Vertex |
angles that are opposite each other when lines intersect. (congruent) | Vertical Angles |
use a compass to find the midpoint of a line Line Segment | Bisect |
a device used to draw arcs and circles | Compass |
points that are on the same line | Collinear |
figures that are on the same plane |
Coplanar |
Lines that cross at a vertex | Intersecting |
a group of points that follow a never ending, straight path | Line |
lines from the same plane that will never cross | Parallel |
Intersecting lines that form a set of right angles. | Perpendicular |
an endless flat surface that is named by any 3 points. | Plane |
an exact location in space | Point |
a part of a line with one end point | Ray |
a part of a line with 2 end points | Line Segment |
lines that are not on the same plane. | Skew |
parallel lines that are crossed by an intersecting line | Transversal |
a triangle with all angles less than 90o | Acute Triangle |
two shapes of exactly the same size and proportions | Congruent |
line segment that connects two nonadjacent vertices of a polygon | Diagonal |
a triangle with all sides the same measure | Equilateral Triangle |
a six sided polygon | Hexagon |
a triangle with 2 sides the same measure | Isosceles Triangle |
a triangle with one angle that is greater than 90o | Obtuse Triangle |
an 8 sided polygon | Octagon |
a quadrilateral with 2 pairs of parallel sides | Parallelogram |
a five sided polygon | Pentagon |
a closed plane figure made by three or more line segments | Polygon |
a four sided polygon | Quadrilateral |
a parallelogram with four 90o angles | Rectangle |
a polygon in which all sides and angles are congruent | Regular Polygon |
a parallelogram with 4 equal sides | Rhombus |
a triangle with one angle that is 90o | Right Triangle |
a triangle with no side having an equal measure | Scalene Triangle |
a rectangle with 4 equal sides | Square |
a quadrilateral with only 1 pair of parallel sides | Trapezoid |
common endpoints that form a "corners" of a polygon | Vertices |
the line a figure is "flipped" over | Line of Reflection |
a line that divides a figure in such a way as to create 2 congruent or matching figures. | Line of Symmetry |
move or change the position of a figure | Transformation |
slide a figure | Translation |
flip a figure (mirror image) | Reflection |
turn a figure around a point. | Rotation |
figures have the same shape - may not have the same size | Similar |
a repeating arrangement of one or more shapes that completely covers a plane - no gaps or over laps | Tessellation |