I don't suppose you made a sketch . . .
Prove analytically that the diagonals of a square are of equal length,
bisect each other, and are at right angles.
D(0,a)* - - - - - *C(a,a)
- - * - - - - - * - -
Use the Distance Formula to compare the lengths of and
Write the equation of diagonals and
. . and locate their intersection,
Then use the Distance Formula to show that: . and
You already have the equations of and
. . Simply show that they are perpendicular.