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At a Glance

The area of a regular pentagon looks about twice as a big as the pentangle star drawn within it. Is it?

Darts and Kites

Explore the geometry of these dart and kite shapes!

No Right Angle Here

Prove that the internal angle bisectors of a triangle will never be perpendicular to each other.

Pegboard Quads

Age 14 to 16
Challenge Level

An article by Paul Andrews, "Angle Measurement: An Opportunity for Equity" , provides the best notes for background to this problem and all the Stage Three problems this month.
link to go here to ID 2855