Supplementary & Complementary Angles

Supplementary & Complementary Angles

Lets rewind to class last week and discuss how to name geometric figures...

Ray→
Endpoint + point on ray

Line  $\leftrightarrow$  
Any two points on the line

Line Segment  $\overline{xy}$ 
Point that begins + point that ends

RAY

 $\overrightarrow{AB}$  

LINE SEGMENT

 $\overline{AB}$  

LINE

 $\leftrightarrow$  

 AB

COMPLEMENTARY

two angles are complimentary when adding their measure of degree together equals 90.

SUPPLEMENTARY

two angles are supplementary angles when adding their measure of degree equals 180.

Multiple Choice

<ABC and <FAD are supplementary angles, and <ABC = 90 degrees, what is the measure for <FAD?

• 180

• 90

• 100

• 0

We know that these two angles are supplementary angles because added together they will equal 180 degrees (a straight line). To solve this equation, add both of these expressions together and set them equal to 180.
 $2x+3+x-6=180$  

 $3x\ -3=180$  
 $3x=183$  
 $x=61$  

Once we solve for x, we can now substitute x in to find out the measure for each angle.

2(61) + 3 = 125
(61) - 6 = 55
The angle to the left is 125 degrees 
The angle to the right is 55 degrees

Added together they equal 180 degrees

Multiple Select

Use the right angle on the previous slide to answer the following questions.

What is the solution for x?

What is the measure for the two angles shown?

• x = 60

• x = 30

• x = 90

• angles = 30 & 60 degrees

• angles = 20 & 70 degrees

Use the image on the right to answer the following question on the next slide

Multiple Select

Identify which angles are obtuse angles

• <DOB

• <AOC

• <COB

• <DOA

Multiple Select

Using the same image, identify which angles have the same measure of degrees.

• <DOB & <AOC

• <BOC & <DOB

• <AOC & <AOD

• <DOA & <BOC