Angles, Polygons, + Quadrilaterals Flashcards
If two lines never cross, they are
Parallel
If two lines cross, we say they
Intersect
If two lines make corners at the point where they cross, the lines are
Perpendicular
Angles made by perpendicular lines
Right angles
An angle less than a right angle
Acute
Greater than a right angle
Obtuse
Degrees in a straight line
180
Degrees in a circle
360
Polygon with an indention
Concave
Polygon with no indention
Convex
4 sided figure
Quadrilateral
5 sided
Pentagon
Six sided
Hexagon
Seven sided
Heptagon
Eight sided
Octagon
Nine sided
Nonagon
Ten sided
Decagon
Eleventh sided
Undecagon
Twelve sided
Dodecagon
N sided figure
N-gon
Polygon whose side are equal in length
Equilateral
Polygon whose angles have equal measure
Equiangular
Polygon with both equal sides an angles
Regular polygon
Triangle with one ninety degree angle
Right
Three angles less than ninety degrees
Acute
Triangle with one angle more than ninety degrees but less than 180
Obtuse
Triangle with all angles equal in measure
Equiangular
Triangle with three sides of equal length
Equilateral
Two sides of equal length
Isosceles
No side of equal length
Scalene
Sum of the angles of any triangle
180*
