Distance from a Point to a Line

Lesson 42

Going Over HW

• Please discuss with your group

how to find the distance from a line

to a point not on the line.

• Is there a process?

• Does graph paper help?

• Does slope play a factor?

• Is there a formula?

Essential Question

• How do I find the distance

between a line and a point not on

the line?

Activator

Use graph paper or a grid board to determine the distance between the point P(3, 6) and:- the line x = 8- the line y = 4- the line y = 2x

L42 Theorems

L42 Theorems

L 42 Demonstration Ex. 1

a. Find the distance from P(6, 4) to the line y = 1.b. Find the distance from P(6, 4) to the line x = 1.c. Find the distance from P(6, 4) to the line y = x.

L 42 Demonstration Ex. 2

Given the equation

y = 2x + 1 and the

point S(3, 2), find:

• the point on the line

that is closest to S

• the shortest distance

from S to the line.

Is there a shortcut? YES!

Watch this video.

L 42 Shortcut Method Ex. 2Given the equation y = 2x + 1 and the point S(3, 2), find the point on the line that is closest to S. Find the shortest distance from S to the line.

Your turn! Shortcut method

Find the distance from point P(7, -3) to the line y = 3/4x - 2.

Partner Practice Problems

p. 277 #15, 16, 23. Please use graph paper. Copy each problem. Show reasoning.

Exit Slip: Quick Quiz

- Find the distance

between the line y = -

4/3x + 2 and the point

(4, 5).