Drag diagonals out of one vertex to fan a polygon into 180° triangles and dial the interior sum, then walk the exterior angles round a 360° gauge to find the missing turn.
One vertex of a quadrilateral, pentagon, hexagon or octagon is the hub; the player drags or taps a diagonal to every non-adjacent vertex and each new triangle fills in with its 180°, so (n − 2) · 180° is derived by counting rather than recalled, and then dialled as the interior angle sum. Regular-polygon rounds fan the same way and share the sum equally across the n angles, while walk rounds move a walker round the perimeter so every exterior angle stacks into a circular gauge and the missing turn is read from the gap to 360°. It targets the 'one triangle per side' overcount and the belief that exterior angles grow with the number of sides. Best for Grades 7–8.
A free, no-signup, no-ads math game for Grades 7–8 — practising angle-sum, polygons, exterior-angle, regular-polygons, triangulation. Play in your browser on the KidsDoMath games hub or explore more Geometry & Shapes games.
By grade level: 7th Grade Math Games8th Grade Math Games
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What math does Polygon Angle Plaza practice? Polygon Angle Plaza practices Angle Sum, Polygons, Exterior Angle, Regular Polygons. One vertex of a quadrilateral, pentagon, hexagon or octagon is the hub; the player drags or taps a diagonal to every non-adjacent vertex and each new triangle fills in with its 180°, so (n − 2) · 180° is derived by counting rather than recalled, and then dialled as the interior angle sum.
What grade is Polygon Angle Plaza for? Polygon Angle Plaza is built for Grades 7–8 (ages 12–14). It sits in the Geometry & Shapes strand, and it ramps across 8 levels so younger or older players find their own pace.
How do you play Polygon Angle Plaza? Drag diagonals out of one vertex to fan a polygon into 180° triangles and dial the interior sum, then walk the exterior angles round a 360° gauge to find the missing turn.
Is Polygon Angle Plaza free to play? Yes. Polygon Angle Plaza is free, with no ads and no sign-up, and it runs in the browser on a phone, tablet or computer.