Question

Please help! Rhombus or Rectangle??

Answer 1

The length of the diagonals are the same so it's definitely a square, and all squares are rhombuses. However, all squares are also rectangles.

Each angle is a right angle, so you have
\[\begin{cases}2xy=90\\
9x+9=90\end{cases}\]
The second equation gives \(x=9\), and plugging into the first gives \(18y=90~~\iff~~y=5\).