Question

Are the links 5 yards 12 yards and 13 yards a right triangle?

Answer 1

yes it is a right triangle

Answer 2

You will have to verify by using the Pythagorean theorem.
a^2+b^2=c^2
5^2+12^2=13^2
25+144=169
169=169
So, yes, they are links of a right triangle.