Question

Check my answer?
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This problem is using the Pythagorean Theorem.

Answer 1

yes

Answer 2

A quick check that works for many cases (but not all):
Take the square of the smallest number. If it is odd, square it and divide by two.
If you add and subtract to the half and get the other two numbers, then it is a right triangle.
Example:
3^2=9, 9/2=4.5, 4.5-.5=4, 4.5+.5=5, so (3,4,5) is a Pythagorean triplet.
Another:
7^2=49, 49/3=24.5, 24.5-.5=24, 24.5+.5=25, so (7,24,25) is a Pythagorean triplet.
... etc.