Given the triangle:
The relationship between a, b and c can be found using the cosine rule, that is,
[tex]\begin{gathered} c^2=a^2+b^2-2ab\cos C \\ C=90^0\lbrack\text{right angle\rbrack} \\ \therefore c^2=a^2+b^2-2ab\cos (90^0) \\ or,\text{ }c^2=b^2+a^2-2ab\cos (90^0) \end{gathered}[/tex]
Therefore, the correct answer choice is option C
