Pre Algebra Periods 1, 2, & 4

CHAPTER 9
GEOMETRY
I will go over in class the symbols of each of the following
Point:(symbol is a dot or just a letter) Location in space - no size
Ray: (arrow pointing to the right) - one endpoint and one direction- Named by its endpoint first
Line: (generally, line with arrows on both ends above 2 points on the line) - Series of points that goes on infinitely in both directions - named either direction
Line segment: (a line with no arrows on either end) - a piece of a line with 2 endpoints in either direction
Lines can be parallel (2 vertical lines) or intersecting in the same plane
Parallel lines are lines in the same plane that never meet
If they intersect at exactly 90 degrees, then they are perpendicular
If they don't intersect but are in two different planes, they are skew
angle: (angle opening to the right) two rays that meet at the same endpoint
named by either just the vertex, or 3 points on the angle in either direction with vertex in middle
adjacent angles share one ray
vertical angles are opposite each other and congruent (equal)
Complementary sum to 90 degrees and
Supplementary sum to 180 degrees
acute is greater than 0 degrees and less than 90 degrees
90 degrees is right angle
obtuse is greater than 90 degrees but less than 180 degrees
180 degrees is a straight angle (line)
to write the measure of an angle you write m<