Chapter 1 - Essentials of Geometry Flashcards
Point
No dimension, place in space
Lines
Has one dimension
Planes
Have two dimensions
Collinear
CAN be drawn on the same lines
Coplanar
Points on the same plane
Undefined Term
A term (ex point or line) with no formal definition, but we all roughly agree on what it is
Line Segments
Has two end points, name by end points
Rays
Has one end point, goes on forever. Name using endpoint and one point on the line, ORDER MATTERS
Lines or Opposite Rays
Two rays that share an endpoint forming a line, name with two points on the line
Intersections
When two or more figures share a point or line
Postulate
A rule that is accepted with proof
Theorem
A rule that can be proved
Segment Addition Postulate
The parts of a segment add up to the whole segment (if B is between A and C, then AB + BC = AC)
Congruent Segments
Line segments with the same length (shown using hash marks)
Midpoint
A point that divides the segment into two congruent (equal) segments
Segment Bisector
A point, line, Ray, segment or plane that crosses a segment at its midpoint
Midpoint Formula
X1 + X2 Y1 + Y2
——– = ———
2 2
Pythagorean Theorem
a^2 + b^2 = c^2
Distance Formula
Square Root of (X2 - X1)^2 + (Y2 - Y1)^2
Angle
Created when two different rays have the same endpoint, the amount of rotation from one Ray to another
Vertex
The point when two rays meet; the “middle point”
Sides
Two rays making up the angle
Angle units
Degrees
Acute Angles
Between 0 and 90 degrees
Obtuse
Between 90 and 180 degrees
