Diagonals of a rhombus are equal. Is this rhombus also a square?

The perimeter of a parallelogram is $60 \mathrm{cm}$. If the smaller side is $12 \mathrm{cm}$ long, find the measure of the longer side.

In the figure, find the four angles $A, B, C, D$ of the parallelogram $ABCD$.

In the figure, find the value of$a$ and $b$ and measure of $\angle \mathrm{Q}$ of the parallelogram $\mathrm{PQRS}$.