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In your NOTEBOOK!!!. Write the following two puzzles, and try to solve them quietly: Example: He’s/Himself = “He’s beside himself” 1. ANGLE 2. LAWMOTHERLAW ANGLE ANGLE. Lesson 4.1 – Triangle Sum. Today’s Goal. Formally define a triangle and begin finding missing angles! WHY?
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In your NOTEBOOK!!! Write the following two puzzles, and try to solve them quietly: Example: He’s/Himself = “He’s beside himself” 1. ANGLE 2. LAWMOTHERLAW ANGLE ANGLE
Today’s Goal • Formally define a triangle and begin finding missing angles! • WHY? • Triangles are the only rigid polygon
New Material – VOCAB SECTION B A C 2 3 1
In your Notes • How to find the missing angle • Step 1: Add two given angles. • Step 2: Subtract sum from 180. • Step 3: This is the missing angle. y S1: 60 + 70 = 130 S2: 180 – 130 = 50 S3: y = 50° 70° 60°
In your Notes… • Copy down the following drawings and identify why it is NOT A TRIANGLE… WARNING: There may not be a problem! i.e. It might be a triangle! 2. 1. 50° 75° 55° Not a closed figure! No problems!
3. 4. 30° 50° Has 4 sides, not 3 Angles don’t add to 180 6. 5. 33° 97° 30° 20° 87° 60° Angles don’t add to 180 No Problem!
Problem of the Day • What is the value of z in the picture below? • 32° • 58° • 122° • 180°
Homework Lesson 4.1/ 1 – 9 Vocabulary