- Before this lesson make copies of the parallelograms and trapezoids.
- I give each student a copy of these shapes and a pair of scissors.
- I remove the words in italics on students’ notes before I print them.
I want students to take time to figure out a strategy to find the area of the parallelograms and trapezoids. Some students will split a parallelogram into two triangles and a rectangle to find the area. Other students may count the whole squares and ½ squares. Other students may recognize they can move one of the triangles to the other side of the shape to create a rectangle to find the area. Students are engaging in MP8: Look for and make sense of repeated reasoning.
For the trapezoids some students may create two triangles and a rectangle. Some struggling students may try to estimate the area by counting whole squares and partial squares. Other students may recognize that with trapezoid III they can move a triangle to create a rectangle, although this strategy does not work with the other trapezoids.
I choose students to share their strategies under the document camera. I look for a student who created rectangles and triangles. I also look for a student who moved a triangle to create a rectangle. If no one uses this strategy I cut out the parallelogram and show them.
When I define parallelogram I also introduce the formula for area of base times height. When I introduce the trapezoid I do not introduce a formula. I find that many students get confused with this formula. Instead, I encourage students to break trapezoids up into triangles and a rectangle/square.
Если ты хочешь назначить мне свидание, я освобожусь. Если же нет, то позвони электрикам. - Джабба, дело очень серьезное. У меня чутье. У нее чутье.