SECTION 2.4Vertical Angles

LEARNING TARGETS:1. Students will be able to use and apply the Vertical Angles Theorem.2. Students will be able to use and

apply the Linear Pair Postulate.

VOCABULARYVertical Angles and Linear Pair

Question:◦What is the relationship between the angles formed by two intersecting lines.

Materials:◦Paper◦Straightedge◦Protractor

Page 74

STEP 1:

STEP 2:

STEP 3:

THINK ABOUT IT

VOCABULARY:

Vertical Angles:◦Two angles that are not adjacent and whose sides are formed by two intersecting lines.

Which of the above angles are vertical?

VOCABULARY:

Linear Pair:◦Two adjacent angles who non-common sides are on the same line.

Which of the above angles are linear pairs?

Example (Notes)

Example (Textbook)

Linear Pair Postulate◦If two angles form a linear pair, then they are supplementary.

Postulate 7:

Example (Notes)Find the measure of ∠ RSU.

Find the measures of HJK∠ and KJN∠ .

Vertical Angles Theorem

Theorem 2.3:

PROOF OF THEOREM:

Example (Textbook)

Example (Notes)Find m∠1, m∠2, and m∠3.

Example (Notes)Find the value of x.

Example (Notes)Find the value of x.

Example (Notes)Find the value of x.

DAILY PUZZLER:When two lines intersect, the measure of one of the angles they form is 20° less than three times the measure of one of the other angles formed. What are the measures of all four angles formed by the two lines?

Vertical Angles WorksheetCooperative Learning:

Section 2.4 AssignmentPage 78 #10-50 EVEN, 51-56 ALL

Due Tuesday, 10/25

HOMEWORK: