Unit 5 Notes Day 7

Course 3

7-5 Coordinate Geometry

Slope is a number that describes how steep a line is.

slope = vertical change horizontal change

rise run=

Warm UpComplete each sentence.

1. Two lines in a plane that never meet are called ______________lines.

2. ___________________ lines intersect at right angles.

3. The symbol || means that lines are _________________.

4. The symbol means that the lines are _________________.

Slopes of Parallel and Perpendicular Lines

Two lines with equal slopes are parallel.

Two lines whose slopes have a product of –1 are perpendicular.

If a line has slope , then a line perpendicular to it has slope – .

Helpful Hint ab

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Course 3

7-5 Coordinate Geometry

Additional Example 2: Finding Perpendicular Line and Parallel Lines

Which lines are parallel? Which lines are perpendicular?

slope of EF = – 32

slope of GH = 35

slope of PQ = 35

slope of QR = or –1 3 –3

slope of CD = 2 3