What is the missing justification in the proof of the pythagorean identity below, sin^2(x)+cos^2(x)=1, using a right triangle? a. transitive property of equality b. substitution property of equality c. reflexive property of equality d. symmetric property equality

You have to jusitfy the step that leads from sin (x) = a/c and cos(x) = b/c to sin^2 (x) + cos^2(x) = [a^2 / c^2] + [b^2 / c^2].

As you can see go from the first statement to the second by substituting the value of sin(x) by a/x and the value of cos(x) by b/c.

Then, the answer is the option b. substitution property of equality.