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HW-Pg. 175 (2-8)
Quarterly Tuesday 11-13-12
www.westex.org HS, Teacher Websites
11-7-12
Warm up—Geometry CPA
1. Which two angles are vertical angles?
(A) SPT and TPU (B) RPS and UPQ
(C) RPQ and TPU (D) RPQ and SPT
2. Point P is the midpoint of RS . If RP = 2x + 1 and
RS = 5x - 2, what is PS ?
(A) 3
(B) 6
(C) 4
(D) 9
3. How many segments are skew to AE ?
(A) 1
(B) 3
(C) 2
(D) 4
GOAL:
I will be able to:
1. prove and apply theorems about perpendicular
lines.
HW-Pg. 175 (2-8)
Quarterly Tuesday 11-13-12
www.westex.org
HS, Teacher Websites
Name _________________________
Geometry CPA
3-4 Perpendicular Lines
Date ________
The _________________________ of a segment is a line perpendicular to a segment at the
segment’s midpoint.
The shortest segment from a point to a line is perpendicular to the line. This fact is used to
define the ____________ from a point to a line as the length of the perpendicular segment
from the point to the line.
Example 1: Distance From a Point to a Line
A. Name the shortest segment from point A to BC.
B. Write and solve an inequality for x.
You Try:
A. Name the shortest segment from point A to BC.
B. Write and solve an inequality for x.
Example 2: Proving Properties of Lines
Write a two-column proof.
Given: r || s, 1  2
Prove: r  t
You Try:
Write a two-column proof.
Example 3: Carpentry Application
A carpenter’s square forms a right angle. A
carpenter places the square so that one side is
parallel to an edge of a board, and then draws a
line along the other side of the square. Then he
slides the square to the right and draws a second
line. Why must the two lines be parallel?
You Try:
A swimmer who gets caught in a rip current should swim in a direction
perpendicular to the current. Why should the path of the swimmer be
parallel to the shoreline?
PRACTICE 3-4
1. Write and solve an inequality for x.
2. Solve to find x and y in the diagram.
3. Complete the two-column proof below.