Grade
3

Guess My Rule: Polygon Sort

A Venn diagram with a red circle and a blue circle. The red circle has a regular octagon. A regular triangle. A regular pentagon. And a regular hexagon.The blue circle has a rectangle, an irregular quadrilateral. A trapezoid. And a parallelogram. Where the circles overlap: A regular parallelogram. A rhombus. And a square.
  1. Some shapes belong in the circles, and some shapes do not. What is the rule to be in the red circle? What is the rule to be in the blue circle? What is the rule to be in both circles?
  2. Draw a shape that doesn’t belong in either circle.
  3. Where would you place this shape? Why?
A 4-sided shape, with unequal side lengths.
  1. Draw another shape that belongs in only the red circle.
  • What do you notice about the number of sides in each shape?
  • What do you notice about the lengths of the sides of each shape?

Make your own rule, using shapes. You can use the circles below or draw your own.

If possible, show some examples that belong inside each circle and some examples that don’t belong in either circle.

An empty Venn diagram The rule for the red circle is blank. The rule for the blue circle is blank.
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Reference for Educators

Sample problems and solutions