Why do this problem?
The first two parts require only applying the idea that the
tangents from an external point to a circle are equal and the
radius is perpendicular to the tangent at the point of
The first two parts could be tackled by the learners
For the third part the formula for generating Pythagorean triples
What facts do you know about tangents to circles?
What do you know about areas of triangles?
What is the formula for generating Pythagorean triples?
Pythagorean Triples I,
Pythagorean Triples II
Picturing Pythagorean Triples.
Pythagoras Mod 5
See the article
which generalises this problem.