Chapter 1 Vocabulary Flashcards
Collinear set of points
a set of points all of which lie on the same straight line
Noncollinear set of points
a set of three or more points that do not all lie on the same straight line.
Distance between two points on the real number line
the absolute value of the difference of the coordinates of the two points
B is between A and C
AB + BC = AC
Line segment
a set of points consisting of two points on a line, called endpoints, and all of the points between the endpoints.
Length or Measure of a Line Segment
The distance between its endpoints
Congruent Segments
segments that have the same measure
Midpoint of a line segment
a point of that line segment that divides the segment into two congruent segments
Bisector or a line segment
any line, or subset of a line, that intersects the segment at its midpoint
Half-line
a set of points on one side of a point
Ray
a half-line including the endpoint
Opposite Rays
Rays that are in the same line that have the same endpoint
angle
two rays having the same endpoint
straight angle
an angle that measures 180 degrees
acute angle
an angle whose measureis greater than zero and less than 90
right angle
an angle whose measure is exactly 90 degrees
obtuse angle
an angle whose measure is greater than 90 degrees and less than 180 degrees
Congruent angles
angles that have the same measure
Bisector of an angle
a ray whose endpoint is the vertex of the angle, and that divides that angle into two congruent angles
Perpendicular lines
two lines that intersect to form right angles
Distance from a point to a line
the length of the perpendicular from the point to the line
Polygon
a closed figure in the plane
triangle
a polygon that has no congruent sides
Scalene triangle
a triangle that has no congruent sides
Isosceles triangle
a triangle that has two congruent sides
Equilateral triangle
a triangle that has three congruent sides
acute triangle
a triangle that has three acute angles
right triangle
a triangle that has one 90 degree angle
obtuse triangle
a triangle that has one obtuse angle
Equiangular triangle
a triangle that has all three angles 60 degrees each
The Undefined Terms
Point, Line, Plane, Set
