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.

Terminology

Age 14 to 16 Challenge Level:
The green triangle is an isosceles triangle while the blue triangle is an equilateral triangle.

Find $a$ in terms of $b$ and $c$.

What can you say about the triangles if $a = b = c$?