22. In the diagram $P Q R S$ is a rhombus. Point $T$ is the mid-point of $P S$ and point $W$ is the mid-point of $S R$. What is the ratio of the unshaded area to the shaded area?
A $1: 1$
B $2: 3$
C $3: 5$
D $4: 7$
E $5: 9$
SolUTion
First draw in the line segment $Q S$ as shown. Since we are told that $T$ is the mid-point of $P S$, the triangles $P T Q$ and $T S Q$ have equal bases. Since they also have the same perpendicular height, their areas are equal.

Similarly, since $W$ is the mid-point of $S R$, we have the areas of triangles $S W Q$ and $W R Q$ being equal. Hence the unshaded area, which is equal to the sum of the areas of triangles $P T Q$ and $W R Q$, is the same as the shaded area, which is equal to the sum of the areas of triangles $T S Q$ and $S W Q$.

Therefore the ratio of the unshaded area to the shaded area is $1: 1$.