In which set of ordered pairs is y a function of x?
A. {(1.25, 6), (3, 6), (5.75, 6), (11,6)}
B. {(2, 15), (3, 12), (4, 10), (4,8)}
C. {(6, 1), (3, 8), (3, 9), (6, 12)}
D. {(6.5, 10), (6.5, 0), (6.5,9), (6.5, 12)}

Given: abcd is a square. prove: ac ? bd. we are given that abcd is a square. if we consider triangle aeb and triangle aed, we see that side is congruent to side ad because sides of a square are congruent. we know that side ae is congruent to side ae by using the . finally, we know that side de is congruent to side because the diagonals of a square bisect each other. therefore, triangle aeb is congruent to triangle aed by congruency. we see that angle aed and angle aeb are a linear pair, and congruent by cpctc. thus, the measure of these angles will be 90°, and diagonal ac is perpendicular to diagonal bd by the .