Stage: 4 Challenge Level: 
The sides of a triangle are 25, 39 and 40 units of length.
Find the diameter of the circumscribed circle.
Long problems. Inscribed polygons. Pythagorean triples. Investigations. Mixed triangles. Stage 5 needs dealing with. Circles. Pythagoras' theorem. Mixed trig ratios. Circle theorems.
Published September 2003.
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