A circle touches the lines OA, OB and AB where OA and OB are perpendicular. Show that the diameter of the circle is equal to the perimeter of the triangle
A 1 metre cube has one face on the ground and one face against a
wall. A 4 metre ladder leans against the wall and just touches the
cube. How high is the top of the ladder above the ground?
The area of a regular pentagon looks about twice as a big as the pentangle star drawn within it. Is it?
What is the order of rotational symmetry of each axis of symmetry?
How may faces are there? So how many axes of symmetry are there that
join two (opposite) faces together?
You are not trying to find the average of just three lengths.