1. Lesson Plan for SD 2.2/2.4 (50 minutes): Target: I can find a missing angle in a triangle. 5 minutesWarm-up (notebook) 10 minutesInvestigate Angle Sum – Have each student complete the angle measurements and sum for one triangle and then share answers with their group. 5 minutesSummarize sum of interior angles and show example of tearing method (tearing off all angles and putting them together to make 180 degrees). 25 minutesGive students time to work on A (review answers). Model at least one part of B (writing equations and finding missing angles). Save some time to go through those answers in detail. 5 minutesReminders: Correct homework with key (puzzle)

2. Quick Start Expectations 1.Learning Target: I can find the measurement of a missing angle in a triangle! 2. Fill in Learning Log HW: 1) Missing Angles in Triangles WS (Inv. 2 packet) -Odd Problems 2) Complete 30 mins of MathXL 3. Warm-up: Simplify these expressions by combining like terms. Example: 2x + 4x 2x + 4x = 6x (simplified answer) a. 8x + 5x + 9x b. 5x + 8 + 2x + (-10) c. -3y + 5x + 8y + 2x + 4z

4. 35° 110° 50°20° 70° 55° 30°60° 90°

5. 180°

6. Equation: 50 + 70 + ___ = 180 ∠ CBA = Equation: ___ + ___ + ___ = ____ ∠ KJL = Equation: ∠ GQW =

7. x + 2x + 3x = 180 6x = 180 x = 30°, 2x = 60, 3x = 90 x + 2x + x – 20 = 180 4x - 20 = 180 4x = 200 x = 50°, 2x = 100, x – 20 = 30 Do not measure! 30° 60°90° 50° 100° 30°

8. S

9. HW: 1) Missing Angles in Triangles WS (Inv. 2 packet) -Odd Problems 2) Complete 30 mins of MathXL