10-2 Complementary and Supplementary Angles.notebook1
10­2: Complementary and Supplementary Angles Please have your homework assignment out on your desk. You have 5 minutes to complete the problems below.
10­2 Complementary and Supplementary Angles.notebook
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February 24, 2014
Assignment p. 512­513, #1­17, 21,22,26 1.   MNP,  PNM,  N, 1, obtuse
2.   RST,  TSR,  S, 3, acute 3. 1 and 3, or  2,and 4
4.   ABC,  CBA,  B, 4, acute
5.   DEF,  FED,  E, 5, right
6.   XYZ,  ZYX,  Y, 6, obtuse 7.   MNP,  PNM,  N, 7, straight
8.   HKI,  IKH,  K, 8, obtuse
9.   RTS,  STR,  T, 9, acute
10. Vertical
11. Neither
12. Adjacent
13. Adjacent
14. Neither
15. Vertical
17.   1 and 2
3
Main Idea: identify complementary and supplementary angles and find missing angle measures.
Vocabulary: • complementary angles ­ two angles are complementary if the sum of their measures is 90 degrees. • supplementary angles ­ two angles are supplementary if the sum of their measures is 180 degrees.
10­2 Complementary and Supplementary Angles.notebook
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February 24, 2014
Complementary angles Two angles are complementary if the sum of their measures is 90 degrees. One of the complementary angles is said to be the complement of the other. Example: These two angles are complementary.
Note that these two angles can be "pasted" together to form a right angle!
10­2 Complementary and Supplementary Angles.notebook
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90o
45o45o
6
x
x
Solution
If the sum of the measure of 2 angles is 90o  the angles are called complementary angles.
10­2 Complementary and Supplementary Angles.notebook
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27o
8
February 24, 2014
Supplementary angles Two angles are supplementary if the sum of their measures equals 180 degrees. One of the supplementary angles is said to be the supplement of the other. Example: These two angles are supplementary.
Note that these two angles can be pasted together to form a straight line!
10­2 Complementary and Supplementary Angles.notebook
9
90o
45o45o
10
S
S
Sx
x
Solution
If the sum of the measure of 2 angles is 180o  the angles are called supplementary angles.
10­2 Complementary and Supplementary Angles.notebook
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12
February 24, 2014
7x + 5x = 90 12x = 90 x = 7.5 The larger angle is 52.5o The smaller angle is 37.5o
5x + x = 90 6x = 90 x = 15 The smaller angle is 15o The larger angle is 75o
Word problems
Two angles are complementary. The larger angle is 5 times  greater than the smaller angle. Find the measure of the 2 angles.
Two angles are complementary. The measure of the angles are in a ratio of 7:5. Find the measure of the angles.
10­2 Complementary and Supplementary Angles.notebook
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x = 34
Supplement is 146o
8x + x = 180 9x = 180 x = 20 The smaller angle is 20o The larger angle is 160o
Word problems
Two angles are supplementary. The larger angle is 8 times  greater than the smaller angle. Find the measure of the 2 angles.
The measure of the supplement of an angle is 10o more than four times the original angle. Find the measure of the two angles.
10­2 Complementary and Supplementary Angles.notebook
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p. 516­517, #1­13, 23 and 24
Quiz tomorrow over Lessons 10­1 and 10­2  (Angle Relationships, Complementary and  Supplementary Angles)
10­2 Complementary and Supplementary Angles.notebook
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1. Supplementary
2. Complementary
Subject Mathematics Grade 7 Strand Geometry
Objective The objective of this lesson is to compute angle complements and supplements.
Page 1 Title page.
Page 2 Ask a student volunteer to identify the diagrams which show complementary angles. The letter C in the blue circle can be used to identify the angles. If students need to review the definition of a complementary angle this can be dragged from the side of the screen.
Page 3 Solution to previous page. Ask students to explain why the angles marked with an ‘x’ are not complementary angles.
Page 4 “How do you find the measure of the complement of an angle?” (Subtract its measure from 90 degrees.) Find the complement of the angles. Write the answers in the blue boxes using the Pen Tool. Click each of the answer buttons to check your answer.
Page 5 Solve the word problems involving complementary angles. Drag the hint button from the left of the page.
Page 6 Ask a student volunteer to identify the diagrams which show supplementary angles. The letter C in the blue circle can be used to identify the angles. If students need to review the definition of a supplementary angle this can be dragged from the side of the screen.
Page 7 Solution to previous page. Ask students to explain why the angles marked with an ‘x’ are not supplementary angles.
Page 8 “How do you find the measure of the supplement of an angle?” (Subtract its measure from 180 degrees.) Find the supplement of the angles. Write the answers in the blue boxes using the Pen Tool. Click each of the answer buttons to check your answer.
Page 9 Solve the word problems involving supplementary angles. Drag the hint button from the left of the page.
Page 10 “Which angles facts did you use to solve this problem?”
SMART Notebook
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