1. You have a 4-foot-by-7-foot rectangular rug in your 4. Use the area formula for rectangles and the moving third-grade classroom. You also have a bunch of and additivety principles to explain why the arca of square foot tiles the triangle in Figure 12.82 is ! . bok square units a. Your students are just learning about what area for the given choices of base b and height h means. How could they use what arca means to determine the area of the rug? h. Your students have learned about multiplica- tion in terms of equal groups For example, they know that 5-6 means the number of things in 5 groups of 6 things How could your students explain why we can multiply to determine the area of the 4-foot-by-7-foot rectangular rug? Figure 12-82 c. Later, your students will learn the area formula for rectangles Discuss how to relate this area 5. Determine the area of the shaded triangle in formula to your explanation in part (b). Pay Figure 12.83 and explain your reasoning special attention to the different units that are involved. 2. Explain how to use the moving and additivety prin- ciples and the area formula for rectangles (but no other formulas) to determine the arca, in square units of the shaded shape in Figure 12.80. Figure 12.83 6. Explain clearly why there can be no formula for the area of a parallelogram that is only in terms of the units G unit lengths of the sides of the parallelogram. Figure 12.80 7. Explain why the area of the parallelogram in 3. Use the area formula for rectangles and the moving Figure 12.84 ish X h for the given choice of base & and additivety principles to explain in two different and height & You may une the moving and additive ways why the area of the triangle in Figure 12.81 is ity principles and the area formulas for rectangles 4 . bob square units for the given choices of base b and triangles in your explanation (use any or all of and height & One way should fit naturally with the formula both. the other with } (b .#]. Figure 12.81 Figure 12.84 <