Lesson 6

Sampling and Proportions

Est. Class Sessions: 4

Daily Practice and Problems

Teacher Notes
X

TIMS Task

  1. 30 cm; Possible response: I know that the width of the rectangle will be 9 cm because 6 cm × 9 cm = 54 sq cm. To find the perimeter I added (2 × 6) + (2 × 9) = 12 + 18 = 30 cm
  2. 36 sq cm. If the perimeter is 24 cm, each side will be 6 cm. 6 cm × 6 cm = 36 sq cm.
  3. I drew a 5 cm × 5 cm rectangle with an area of 25 sq cm and a 6 cm × 4 cm rectangle with an area of 24 sq cm.
  4. I drew a 8 cm × 4 cm rectangle with an area of 32 sq cm.
  5. I drew a right triangle that is 8 cm × 6 cm with an area of 24 sq cm. 8 × 6 × 1/2 = 24.
  6. Area = 10 sq cm

The area of all three triangles will be the same: 10 sq cm.

FF. Geometry Problems

You will need a centimeter ruler to complete these problems.

  1. The length of a rectangle is 6 cm. Its area is 54 sq cm. What is its perimeter? Show how you found your answer.
  2. The perimeter of a square is 24 cm. What is the area of the square? How did you decide?
  3. Draw two different rectangles each with a perimeter of 20 cm. Find the area of each of your rectangles.
  4. Draw a rectangle that has a width of 4 cm and a length that is twice the width. What is the area?
  5. Draw a right triangle with a base of 6 cm and a height of 8 cm. What is the area? Write a number sentence to show how you solved this.
  6. Make a right triangle, an acute triangle, and an obtuse triangle. Each triangle will have a base of 5 cm and a height of 4 cm. What is the area of all three triangles?