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ABCD
Try it on the Geometry BoardUses:Midpoint and perpendicular bisector

Centre of spiral similarity

Marks the centre of the turn and scaling that takes one segment onto another. Ruler and compass only.

All parts
Part 1 of 8: Rule AC and BD and mark where they meet (X)Step 1 of 5Ruler

Start with two lines. Lay the ruler so its edge passes through A and C.

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