Glencoe Geometry Chapter 1 Vocabulary
Circumference Formula
C = 2πr
angle bisector
a line or line segment that cuts an angle into exactly two angles with equal measure
concave polygon
a polygon that has one or more sides that go into the interior of the polygon
acute angle
an angle measuring less than 90 degrees
perpendicular
at an angle of 90° to a given line, plane, or surface.
vertical angles
congruent two nonadjacent angles formed by two intersecting lines
supplementary angles
Two angles whose sum is 180 degrees
convex polygon
A convex polygon is defined as a polygon with all its interior angles less than 180°.
perimeter
The distance around the outside of a figure.
line segment
pg 13 a measurable portion of a line, with two endpoints
congruent
pg 15 having the same size and same shape
midpoint
pg 22 The point that divides a segment into two congruent segments
segment bisector
pg 25 a segment, ray, line, or plane that intersects a segment at its midpoint
exterior angle of a triangle
pg 31
obtuse angle
pg 32 An angle that measures more than 90 degrees but less than 180 degrees 180> m ∠ C >90
right angle
pg 32 an angle that measures 90 degrees
complementary angles
pg 42 two angles who's measures add up to 90 degrees are said to be ___________.
plane
pg 6 An endless flat surface
coplanar
pg 6 points or lines that are on the same plane are said to be ___________.
collinear
pg 6 points that lie on the same line are _______.
adjacent angles
two angles that share only a side