Objectives

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Objectives
3.8 Analyzing Polygons With Coordinates

• Develop and use theorems about equal slopes and
  slopes of perpendicular lines.
• Solve problems involving perpendicular and
  parallel lines in the coordinate plane by using
  appropriate theorems.

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Glossary Terms
3.8 Analyzing Polygons With Coordinates

• hypotenuse
• rise
• run
• slope

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Theorems, Postulates, Definitions
3.8 Analyzing Polygons With Coordinates
Definition of Slope The slope of a nonvertical
line that contains the points (x1, y1) and (x2,
y2) is equal to the ratio
Parallel Lines Theorem 3.8.2 Two nonvertical
lines are parallel if and only if they have the
same slope. Any two vertical lines are parallel.
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Theorems, Postulates, Definitions
3.8 Analyzing Polygons With Coordinates
Perpendicular Lines Theorem 3.8.3 Two
non- vertical lines are perpendicular if and only
if the product of their slopes is 1. Any
vertical line is perpendicular to any horizontal
line.
Midpoint Formula The midpoint of a segment with
endpoints (x1, y1) and (x2, y2) has the
following coordinates
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Key Skills
3.8 Analyzing Polygons With Coordinates

• Use slope to determine whether lines and
• segments are parallel or perpendicular.

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A quadrilateral has vertices A(2, 3), B(6, 4),
C(8, 7), and D(4, 6). Is ABCD a parallelogram?
ABCD is a parallelogram (opposite sides of
quadrilateral ABCD are parallel).