Right-Angled Request

Weekly Problem 26 - 2006
How many right angled triangles are formed by the points in this diagram?
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Image
Right-Angled Request


The figure shows a rectangle PRSU with a line QT, which divides the rectangle into two squares.
How many right-angle triangles can be drawn using any three points P, Q, R, S, T, U as corners?
 


If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.