Tap a shape button to pick a shape. Press "Count the sides!" and we'll count the sides and vertices one by one. Once you're done counting, try the quiz!
Why is a triangle called a "triangle"? The answer is simple โ it has 3 straight lines (sides), and 3 sharp points (vertices) where those sides meet. A square has 4 sides and 4 vertices. For shapes like triangles, squares, pentagons, and hexagons, the number of sides always matches the number of vertices.
A circle is a bit special. It has no straight sides and no sharp vertices โ it's made of just one smooth curve from start to end. That's why a circle is classified differently from a triangle or square. Interestingly, the more sides a shape has, the rounder it starts to look, more and more like a circle.
Tap a shape and press "Count the sides!" to count the sides and vertices one by one, and see for yourself whether the counts always match.