Length of Diagonal in Rectangle

In the coordinate plane, a rectangle is defined by the vertices at the points A(1, 2), B(1, 5), C(4, 5), and D(4, 2). A point P has coordinates (x, y) such that it is inside the rectangle ABCD. If the length of the diagonal AC is represented as $d$, what is the value of $d$?

To find the length of diagonal AC, we can use the distance formula, which is given by:

$$d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}$$

Utilize the coordinates of points A and C to compute the length: