Guess My Rule: Sides & Corners

Some shapes are inside a circle. They are: a square. A rhombus. A trapezoid. And a rectangle. Some shapes are outside the circle. They are: a circle. 2 triangles. And a hexagon.
  1. Some shapes belong in the circle, and some shapes do not. There is a rule to decide what belongs in the circle. What is that rule?
  2. Which shapes belong inside of the circle? Circle them. How do you know?
Shapes to choose from: a hexagon. A rectangle. A rhombus. A cylinder.
  1. Draw at least one more example that belongs outside the circle.

Look at the shapes inside the circle. Count the sides and corners on each shape. What do you notice?

Make your own rule for shapes. You can use the circle below or draw your own.

An empty circle, with the heading 'Rule for my circle.'