Angles in polygons

Make different quadrilaterals on a nine-point pegboard, and work out their angles. What do you notice?

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

Which hexagons tessellate?

Weekly Problem 39 - 2010
If you know three lengths and an angle in this diagram, can you find another angle by calculation?

Three triangles ABC, CBD and ABD (where D is a point on AC) are all isosceles. Find all the angles. Prove that the ratio of AB to BC is equal to the golden ratio.

Weekly Problem 9 - 2012
What is the angle QPT in this diagram?

Weekly Problem 44 - 2010
Extend two of the sides of a nonagon to form an angle. How large is this acute angle?

Explore the geometry of these dart and kite shapes!

How can the school caretaker be sure that the tree would miss the school buildings if it fell?

More Logo for beginners. Learn to calculate exterior angles and draw regular polygons using procedures and variables.