Lesson 1 Ways to Look at Figures

    • Let’s sort two-dimensional figures.

Warm-up Which One Doesn’t Belong: Geometric Figures

Which one doesn’t belong?

  1. Diagram with right angle and 2 unmarked angles
  2. parallelogram
  3. right trapezoid
  4. right triangle

Activity 1 Card Sort: Shapes

  1. Sort the shapes from your teacher into 3–5 categories. For each category, write a title on a sticky note.

  2. Share your categories with another group. Take turns listening to each other’s explanations.

    • Do your categories make sense to them?

    • Do their categories make sense to you?

    • Any suggestions or corrections?

  3. Cover or hide the titles of your categories. Trade places with another group. Study their sorted cards while they study yours.

    Guess their categories and how they sorted the shapes.

Activity 2 Guess the Category

Partner A:

  • Write down a category from the first activity (or think of a new one). Don’t show it to your partner.

  • Find 3 shapes that fit the category and 3 shapes that don’t. Place them in the columns of the table.

Partner B:

  • Study the shapes chosen by your partner.

  • Pick another shape from the set. Ask: “Does this shape fit in your category?”

  • Find 2 shapes that fit the category and 2 shapes that don’t.

  • Guess the category. If your guess is off, ask more questions before guessing again.

Switch roles after the category is guessed correctly.

    • Partner A’s category:

    fit the category

    do not fit the category

    • Partner B’s category:

    fit the category

    do not fit the category

Practice Problem

Problem 1

4 shapes. All have 4 sides.
  1. Name some attributes that these shapes share.

  2. Name some attributes that the shapes do not share.