Since the diagonal of a square are equal to each other, the length of RZ is;
RZ = 5 units.
What is a square?
In Mathematics and Geometry, a square is a type of quadrilateral in which the length of all its four sides are equal in magnitude (congruent) and the sum of all its interior angles is equal to 360 degrees (360°) and it forms a right angle.
Generally speaking, the diagonals of a square bisect each other at a right angle (90 degrees). This ultimately implies that the length of the two diagonals of a square are equal to each other.
In this context, we have the following;
RZ = AP
5x - 15 = 2x - 3
5x - 2x = 15 - 3
3x = 12
x = 12/3
x = 4 units.
Now, we can determine the length of RZ;
RZ = 5x - 15
RZ = 5(4) - 15
RZ = 5 units.