Polygon Area
Polygon Area
Explore the area of irregular polygons with this free interactive math manipulative. Draw a shape on the square grid or drag the corners of the starting polygon. The area updates as the shape changes, helping students connect geometry, measurement, and square units.
How to Use Polygon Area
Select Draw, then tap grid points to add corners. Tap the first corner to close your polygon. Drag the dotted handles to adjust its shape; corners snap to grid points when released. Select Clear to start again, or Show Area to hide or reveal the total.
Find Area by Dividing into Triangles
Select Triangles to divide the polygon into smaller triangles. Each triangle shows its base (b) and perpendicular height (h). Tap a triangle to see its area calculation using the formula: area = ½ × base × height. Add the areas of the triangles to find the area of the whole polygon.
The height meets the base, or an extension of the base, at a right angle. It is not necessarily the length of a triangle’s side. Explore both convex shapes and concave shapes with inward corners. The tool prevents crossing edges to keep the polygon’s area well defined.
Use Polygon Area for classroom demonstrations, independent exploration, and lessons on decomposing shapes. Challenge students to create different polygons with the same area or predict how moving one corner will change the total.
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