Answer: Yes, those sides form a right triangle
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Work Shown:
a^2+b^2 = c^2
15^2+20^2 = 25^2
225+400 = 625
625 = 625
Since the last equation is true, this makes the first equation true for those a,b,c values. Therefore, by the pythagorean theorem converse, this is a right triangle.
Side note: c is always the longest side.
