A five-sided plane figure.
A pentagon is a five-sided shape. It’s a type of polygon, which means all its sides are straight and it forms a closed figure.
Some pentagons have sides and angles that are all the same — these are called regular pentagons.
Others have different side lengths or angle sizes, and we call those irregular pentagons.
Pentagons are two-dimensional (2D), or flat, shapes, so the real-life examples represent pentagons at their surface. Examples include street signs, soccer ball patterns, or even the shape of a home plate in baseball.
We use pentagons to:
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Explore shapes and symmetry in geometry
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Learn about angles and perimeter
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Classify polygons by the number of sides
When Do Students Learn About Pentagons?
Students are introduced to pentagons as part of early geometry lessons focused on identifying shapes.
Grades 1–2 – Recognizing Pentagons
Students begin learning to identify polygons by counting sides and angles, including triangles, quadrilaterals, and pentagons.
Grades 3–5 – Classifying and Drawing Pentagons
Students learn to classify polygons by properties (number of sides, regular vs. irregular) and may be introduced to perimeter and angles of pentagons.
