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

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Explore the geometry of these dart and kite shapes!

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No Right Angle Here

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

Terminology

Age 14 to 16 Challenge Level:

What do you know about the angles in an equilateral triangle?

What do you know about the angles that meet on a straight line?

What do you know about the angles in an isosceles triangle?

Start by filling in the diagram with the information you know.