EXAMPLE 3 Draw a perpendicular line

SOLUTION

Line h passes through (3, 0) and (7, 6). Graph the line perpendicular to h that passes through the point (2, 5).

= 64

= 32

m1 = 6 – 0 7 – 3

STEP 1

Find the slope m1 of line h through (3, 0) and (7, 6).

EXAMPLE 3 Draw a perpendicular line

STEP 2

Find the slope m2 of a line perpendicular to h. Use the fact that the product of the slopes of two perpendicular lines is –1.

m2 =32

– 1

m2 = – 2 3

Slopes of perpendicular lines

23

Multiply each side by

STEP 3

Use the rise and run to graph the line.

EXAMPLE 4 Standardized Test Practice

SOLUTION

The rate at which the skydiver descended is represented by the slope of the segments. The segments that have the same slope are a and c.

The correct answer is D.ANSWER

GUIDED PRACTICE for Examples 3 and 4

4. Line n passes through (0, 2) and (6, 5). Line m passes through (2, 4) and (4, 0). Is n m? Explain.

ANSWER Yes; the product of their slopes is – 1.

5. In Example 4, which parachute is in the air for the longest time? Explain.

SAMPLE ANSWER

Parachute C. It was in the air approximately 1.25 minutes longer than either a or b.

GUIDED PRACTICE for Examples 3 and 4

6. In Example 4, what do the x-intercepts represent in the situation? How can you use this to eliminate one of the choices?

SAMPLE ANSWER

Time of the landing.

b and c are in the air different amounts of time.