Year 2 Lesson Plan 6 - Areas of Composite
Figures
- (5 min) Mental Math
- What is 4 times 6 divided by 2? [12]
- What is 75% of 200? [150]
- What is the perimeter of a pentagon whose sides are 3 in? [15 in]
- What is the perimeter of an equilateral triangle whose sides are 4
in? [12 in.]
- Take the number of sides in a hexagon, multiply by 10, then divide by
2 [30]
- (5 min) Review selected problems from lesson 5 (no more than
3 problems)
- (5 min) Review areas of polygons:
- Pass out the "areas of polygons" handout.
- Discuss the areas of various polygons
- Draw this trapezoid on the board and have the students help you compute the area of this trapezoid:
Use the trapezoid formula: (b1 + b2) h / 2 and
also solve by cutting into two triangles. Draw the diagonal and ask students to compute the areas of the 2 triangles and add. They should add to the same value as the formula.
- (15 min) Discuss areas of composite figures
- Pass out the "areas of composite figures" handout
- Follow the discussion in that handout and have the students work the problems on it. This handout constitutes the in-class exercise.
- Hand out homework as students successfully complete the in-class exercise.
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