Unit 4 Chapter 6 Section 1a Angle Measures.notebook
February 18, 2015
Unit 4
Chapter 6 Section 1a
Angle Measures
Objective: To write and solve equations to find unknown angle measures
Angle(
Angles
): a figure formed by two rays with a
common endpoint
Name
Measure
acute angle
greater than 0 and less than 90
right angle
equal to 90
obtuse angle
straight angle
greater than 90
and less than 180
equal to 180
Unit 4 Chapter 6 Section 1a Angle Measures.notebook
February 18, 2015
Complementary: the sum of the measures of two
o
angles = 90
Example:
1
2
Supplementary: the sum of the measures of two
angles = 180
Example:
o
1
2
Adjacent angles: share a vertex and a side but have no
interior points in common
Example:
1 and
2 are adjacent
1
2
Vertical angles: formed by 2 intersecting
lines and are opposite each other
Example:
1 and
3 are vertical
2
1
3
4
Congruent angles: angles with equal measures
Unit 4 Chapter 6 Section 1a Angle Measures.notebook
February 18, 2015
Examples: Finding Supplements and Complements
1) Tell whether the two angles with the given measurement are complementary, supplementary or neither. a)
65o , 35o
b)
44o , 46o
c) 122o , 58o
2) Find the complement and supplement to the given angle.
a)
15o
b)
64o
c)
35o
3) If A and B are complementary and m A is five times m B, what is m B? Write and solve an equation.
Unit 4 Chapter 6 Section 1a Angle Measures.notebook
February 18, 2015
Finding Angle Measures
4) Find measure of each angle.
Step 1: Write an equation
Step 2: Solve for x
Step 3: Calculate the angle measures
a)
b)
2x
3x ­ 5
c)
35 o
6x + 3
4x + 7
Unit 4 Chapter 6 Section 1a Angle Measures.notebook
February 18, 2015
d)
5x ­ 3
3x + 5
5) You know that B is the complement of A, o
o
that m B = 51 and that m A = (3x ­ 12) . Find x.
Unit 4 Chapter 6 Section 1a Angle Measures.notebook
February 18, 2015
Homework
Textbook Pages 218 & 219, #'s 1 - 18