Aim the observatory arm and read its opening against the corner square — acute, right, or obtuse.
The observatory arm opens to an angle, and the child reads it against a right-angle reference square to classify it — acute (smaller), right (square), or obtuse (wider). Comparing to 90° builds angle sense. Best for Grades 4–6.
A free, no-signup, no-ads math game for Grades 4–6 — practising angles, acute-right-obtuse, classify-angles, right-angle, geometry. Play in your browser on the KidsDoMath games hub or explore more Geometry & Shapes games.
More like this: Solid Station · Angle Pairs Post · Plot Architect.