Constructing an equilateral triangle and a square
- The point that is the right distance from both — 3 tasks
- Four equal sides, two different figures — 3 tasks
- The triangle two circles hand you — 3 tasks
- Where a square’s right angles go — 3 tasks
- When two circles meet — 3 tasks
- Practice — 23 tasks
- Summary — 2 tasks
- Cool-down — 3 tasks
Classroom activities
Things a class does rather than writes on. Each one is a finished PDF: print it, cut it up if it says so, and hand it round.
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Square on a Segment: Where Are the Right Angles? — Cut & Glue Sort 25 minutes, including the cutting · 5 sheets
12 finished squares on a segment, every one drawn exactly square and every mark left on: sort each by what the marks prove — right angles at the corners, a right angle at the middle of the side, or four equal sides and no angle at all. The two commonest wrong squares, side by side with the right one.
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Equilateral Triangle & Square: Do the Marks Prove It? — Mystery Picture 25–35 minutes · 4 sheets
25 strangers' finished constructions of an equilateral triangle or a square on a segment, every arc left on and no numbers: fill the square if the marks prove it, leave it white if they do not — a right angle at the middle of the side, four equal sides and no angle, one circle where two were needed, or a figure drawn by eye that looks perfect.