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Cyclic Quad Jigsaw

A picture is made by joining five small quadrilaterals together to make a large quadrilateral. Is it possible to draw a similar picture if all the small quadrilaterals are cyclic?

Angle Trisection

It is impossible to trisect an angle using only ruler and compasses but it can be done using a carpenter's square.

Beelines

Is there a relationship between the coordinates of the endpoints of a line and the number of grid squares it crosses?

The ELISA Test

Age 14 to 18
Challenge Level

The classroom activities The Dog Ate My Homework and Who is Cheating? contain similar ideas.