Show that the four points given below are the vertices of a rhombus. Show that the four points, $(5, 8), (7, 5), (3, 5)$ and $(5, 2)$ are the vertices of a rhombus.

I tried solving it, by finding out the distances by using the formula $\sqrt{(x_{2}-x_{1})^2 + (y_{2}-y_{1})^2}$

I found all of them but two sides are equal and other two are not. As far as I know, rhombus has all sides equal...but mine does not match! Help please :)
Hint: Here are the points on graph paper.
The sides are formed by joining the points as follows: $(5,8) - (7,5)$, $(7,5) - (5,2)$, $(5,2) - (3,5)$, and $(3,5)-(5,8)$. If you check these four lengths, you will find that they are all equal.