Answer:
a) substitution property of equality
Step-by-step explanation:
It looks like an expression has been formed using the left sides of the first two statements, and then the right sides of those statements substituted into that expression. Hence, it seems the substitution property is the most appropriate choice.
[tex]\sin^2{x}+\cos^2{x}=\sin^2{x}+\cos^2{x}\quad\text{reflexive property}\\\\\sin^2{x}+\cos^2{x}=\dfrac{a^2}{c^2}+\dfrac{b^2}{c^2}\quad\textbf{substitution property}[/tex]
