1.1. Angles are measured in DegreesAngles are measured in Degrees

2.2. Acute AngleAcute Angle - Less than 90 - Less than 90o o but greater than 0but greater than 0oo..

3.3. Right Angle - is 90Right Angle - is 90oo

4.4. Obtuse AngleObtuse Angle - greater than 90 - greater than 90oo but less than 180 but less than 180oo..

5.5. Straight AngleStraight Angle - 180 - 180oo angle angle

6.6. Reflex AngleReflex Angle - Greater than 180 - Greater than 180oo but less than 360 but less than 360oo

Two angles are complementary angles if the Two angles are complementary angles if the sumsum of their measures is of their measures is 9090oo..

Each angle is the complement of the other.Each angle is the complement of the other.

Complementary angles can be adjacent or non Complementary angles can be adjacent or non adjacent.adjacent.

Adjacent

Complementary angles.

Non adjacent

Complementary angles

Two angles are supplementary angles if the Two angles are supplementary angles if the sumsum of their measures is of their measures is 180180oo..

Each angle is the supplement of the other.Each angle is the supplement of the other.

Supplementary angles can be adjacent or non Supplementary angles can be adjacent or non adjacent.adjacent.

Adjacent

Supplementary angles.

Non adjacent

Supplementary angles

When two lines intersect, the opposite angles are When two lines intersect, the opposite angles are equal.equal.

Angle 1 = Angle 2

Angle 3 = Angle 4

Sum of angles is 360o

Angle 1 and 3 are supplementary

Angle 1 and 4 are supplementary

Angle 2 and 3 are supplementary

Angle 2 and 4 are supplementary

a) Complementary angles

b) Supplementary angles

c) Right angles

d) Acute angles

e) Obtuse angles

f) Reflex angles

g) Opposite angles

Use the diagram to name the following Use the diagram to name the following anglesangles.

Calculate the unknown angle Calculate the unknown angle measures.measures..

A)A) B)B)

Calculate the unknown angle Calculate the unknown angle measures.measures..

A)A) B)B)

90 = x + 6090 = x + 60

90 - 60 = x90 - 60 = x

30 = x30 = x

180 = 140 + (x - 30)180 = 140 + (x - 30)

180 = 110 + x180 = 110 + x

180 - 110 = x180 - 110 = x

70 = x70 = x

Calculate the unknown angle Calculate the unknown angle measures.measures..

C)C) D)D)

Calculate the unknown angle Calculate the unknown angle measures.measures..

C)C) D)D)

180 = x + 70180 = x + 70

180 - 70 = x180 - 70 = x

110 = x110 = x

y = 70y = 70

Because oppositeBecause opposite

anglesangles

180 = y + 60180 = y + 60

180 - 60 = y180 - 60 = y

120 = y120 = y

180 = 2x + 60180 = 2x + 60

180 - 60 = 2x180 - 60 = 2x

120 = 2x120 = 2x

60 = x60 = x

Check solutions to Lesson 15(2)Check solutions to Lesson 15(2)

Copy notes to Lesson 16Copy notes to Lesson 16

Do Lesson 16 worksheetDo Lesson 16 worksheet

Check solutions when finished.Check solutions when finished.