Our Area of Triangles and More Lesson Plan equips students to identify and use the formula for the area of triangles, trapezoids, and parallelograms such as the rhombus and other quadrilaterals. This lesson also briefly reviews the application of the commutative property of multiplication in these formulas. Develop sound math practices as student show their work in how they utilized the formulas within their calculations.
Sample Classroom Procedure / Teacher Instruction
- Display for the class a single triangle, and separately, a rhombus, trapezoid, parallelogram, and irregular quadrilateral. Ask students: What does a triangle have in common with the other figures?
- Allow for responses and discussion. Students may recognize the 4-sided figures can be turned into a couple of triangles using a diagonal. Ask: How does this help in finding the areas of the figures?
- Allow for responses and discussion. Lead the discussion to- triangles can be used to create 4-sided figures, which help students find the area of all figures.
- Distribute Area of Triangles and More content pages. Read and review the information with the students. Remind students the rhombus has 4 equal sides. Stress the use of the fraction, ½, in finding the area in most of the formulas. (Review the commutative property of multiplication, it can be done in any order if operations are only multiplication.) You may also review perimeter, which students should already know how to find. Use the additional resources to enhance understanding. Distribute Activity page. Read and review the instructions. Distribute the supplies. Calculators are optional for finding area and perimeter, but students should still show the work. Pair students. Give students sufficient time to complete the work. Circulate through the room checking for understanding and cooperation between pairs of students.
- When completed, collect final pages and randomly distribute to other students for correction. Following correction of work, return the pages to original pairs of students and then review and discuss the final questions.
- Distribute Practice page. Check and review the students’ responses.
- Distribute the Homework page. The next day, check and review the students’ responses.
- In closing, ask: Which of the polygons is your favorite and why? Which would you use for a symbol for a new business and why?
- Allow for responses and discussion.
Common Core State Standards: None for Grade 5 CCSS.Math.Content.6.G.A.1
Class Sessions (45 minutes): At least 3 class sessions.
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