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Lesson A
Geometry Review
Angles
Review of Absolute Value
Properties and Definitions
Definitions
• curve: unbroken connection of points
• line: straight curve that has no ends
• only one line can be drawn that passes through
two points
• segment: portion of a line with two endpoints
Definitions (cont.)
• ray: has one endpoint, and extends indefinitely
in the opposite direction
• plane: flat surface with no boundaries and no
thickness
• parallel lines: lines in the same plane that do
not intersect
• perpendicular lines: lines that intersect in right
angles
Definitions (cont.)
•
•
•
•
•
angle: formed by two rays
straight angle: 180 degrees
right angle: 90 degrees
acute angle: less than 90 degrees
obtuse angle: more than 90 degrees, but less
than 180 degrees
• reflex angle: more than 180 degrees, but less
than 360 degrees
Angles
initial position = 0 degrees
Definitions (cont.)
• adjacent angles: angles that have the same
vertex, share a common side, and do not
overlap
• complementary angles: angles that add up to
90 degrees
• supplementary angles: angles that add up 180
degrees
Definitions (cont.)
• vertical angles: when lines intersect,
these are the angles opposite each other
Example A1
x
y
30
40
Example A2
y
x
50
p
Example A3
110
p
2y
5x
Absolute Value
• all positive numbers have a negative
counterpart (same for negative)
• absolute value is the magnitude a number
is from “zero”
Example A4
• Simplify:
- | -4 | - 2 + | -5 |
Properties
• Commutative Property of Addition
– addition is the same regardless of the order of
the numbers
Example A5
• Simplify:
 2
3
 2   2
2
2