undefined terms
point, line, plane
Collinear
points that reside on the same line
Colpanar
points that reside on the same plane
line segment
a portion of a line with two endpoints
ray
A portion of a line, with one endpoint, that continues without end in one direction
equal
having the same number value
congruent
Having the same size and shape
bisect
a segment cut in two equal parts
Midpoint
The point that bisects a line segment
angle
two rays that intersect at their endpoints
right angle
an angle that measures 90 degrees
acute angle
an angle that measures less than 90 degrees and greater than 0
obtuse angle
An angle that measures more than 90 degrees but less than 180 degrees
protractor
A tool used to measure angles
postulate
a statement that is accepted as true without proof
angle bisector
a ray that divides an angle into two congruent angles
Coordinate Midpoint Property
(x1+x2/2, y1+y2/2)
parallel lines
coplanar lines that do not intersect
skew lines
non-coplanar lines that do not intersect
perpendicular lines
two lines that intersect to form right angles (90º)
complementary angles
2 angles (the measurement) which add up to 90º
supplementary angles
2 angles (the measurement) which adds up to 180º
vertical angles
when 2 lines intersect a pair on non-adjacent angles
linear pairs
2 adjacent angles that form a line
polygon
A closed figure made up of line segments on the same plane
vertex (vertices)
A point where two or more straight lines meet.
diagonal of a polygon
a line segment that connects two non-consecutive vertices (of a polygon)
convex
has all diagonals (of a polygon) inside
concave
not all diagonals are inside the polygon
equilateral
all sides are equal in length
equiangular polygon
all angles are congruent
regular polygon
a polygon that is both equilateral and equiangular