Lesson Plan # 8 - Angle measurement, types of angles and triangles

1. (5 min) Mental Math
2. Divide 18 by 3, multiply by 2, then subtract 2 [10]
3. Multiply 12 by 3, then subtract 6 [30]
4. Add the following numbers: 8, 2 1/2 , 10 , 2 1/2 [23]
5. What is the area of a triangle whose base is 10 inches and whose height is 4 inches? [20 sq. in.]

2. (5 min) Review of selected problems from Homework # 7 (<= 3 problems)
3. (15 min) Introduce angle measurement and triangle types:
1. Hand out the "Angle Measurement" handout.
2. Explain angles and angle types as shown in the handout.
3. Explain that the point of an angle is called its vertex
4. Explain "right" angle and the little box symbol.
5. Ask what half of 90 is, then draw a 45 degree angle.
6. Discuss the angle sequence at the bottom of the handout.
7. Draw an angle on the board that is approximately 60 degrees, then ask the class to estimate it's size. Answers should be between 45 and 90 degrees.
8. Turn the handout over and discuss triangle types.
9. Draw a [55,55,70] isoceles triangle on the board and ask the students what type it is.
Note: you may want to break your discussion between the angle discussion and the triangle discussion in order to do the first page of the in-class exercise first before the triangle discussion.
4. (Remainder of class) In-class Exercise.
5. Hand out homework as students successfully complete the in-class exercise.