Lesson 1

Accessing Areas and Pondering Perimeters

  • Let’s think about rectangles.

1.1: Which One Doesn’t Belong: Quadrilaterals

Which one doesn’t belong? 

A

Trapezoid. Top left and bottom left angles = 90 degrees. Bases = 18 and 9 units. Perpendicular Height = 6 units. 

B

Rectangle. Length = 10 units. Width = 8 units.

C

A square with side length 9.

D

Parallelogram. Base 9 units, height 9 units.

 

1.2: Inspect Some Rectangles

Here are some rectangles.

3 rectangles A, B, C. Rectangle A, side lengths 2, 8. Rectangle B, side lengths 4, 6. Rectangle C, side lengths 1, 9.
  1. Which rectangle has the greatest perimeter?
  2. Which rectangle has the greatest area?
  3. Find a rectangle with the same perimeter, but an even greater area than the previous answer.
  4. For the remaining questions, tables are provided to organize your work. Rectangle D has a perimeter of 32 units.
    1. Find the side lengths of three different possible rectangles that have this perimeter.
    2. Find a pair of side lengths for rectangle D that give the greatest area in square units.
    3. Find a pair of side lengths for rectangle D that give the smallest area in square units.
      length (units) width (units) perimeter (units) area (square units)
  5. Rectangle E has an area of 36 square units.
    1. Find 3 pairs of side lengths that give this area.
    2. Find a pair of side lengths for rectangle E that give the greatest perimeter in whole-number units.
    3. Find a pair of side lengths for rectangle E that give the smallest perimeter in whole-number units.
      length (units) width (units) perimeter (units) area (square units)

 

1.3: Inspect Some Tables

Here are two tables. The first shows some measurements for Rectangle A, with a side length of 5 cm. The second shows some measurements of Rectangle B, which is a square.

  1. Complete the table for Rectangle A and be prepared to explain your reasoning.

    length (cm) width (cm) perimeter (cm) area (sq cm)
    5 1    
    5 2    
    5 4    
    5   20  
    5     40
    5   28  
    5     50
    5 \(x\)    
  2. Complete the table for Rectangle B and be prepared to explain your reasoning.

    length (cm) width (cm) perimeter (cm) area (sq cm)
    1 1    
    2 2    
    3 3    
    4   16  
      8    
          100
      \(x\)    
  3. Sketch the graph of each pair of quantities, where the width is plotted along the \(x\)-axis.

    1. \(x\) and the perimeter of Rectangle A

    2. \(x\) and the area of Rectangle A

    3. \(x\) and the perimeter of Rectangle B

    4. \(x\) and the area of Rectangle B

Blank coordinate grid.
Blank coordinate grid.
Blank coordinate grid.
Blank coordinate grid.

Summary