4. The diagram shows three squares, $P Q R S, T U V W$ and $W X Y Z$. Angles $P U V$ and $Q Y X$ are $62^{\circ}$ and $74^{\circ}$ respectively. What is angle $V W X$ ?
A $44^{\circ}$
B $48^{\circ}$
C $60^{\circ}$
D $64^{\circ}$
E $68^{\circ}$
4. A Note that $P Q Y X W V U$ is a heptagon (seven-sided polygon).
Therefore the sum of its interior angles $=(7-2) \times 180^{\circ}=900^{\circ}$.
Since $P Q R S$ is a square, $\angle U P Q=\angle P Q Y=90^{\circ}$.
Also, since $T U V W$ and $W X Y Z$ are squares, reflex $\angle U V W=$ reflex $\angle W X Y=270^{\circ}$.
So $\angle V W X=(900-2 \times 90-2 \times 270-62-74)^{\circ}=44^{\circ}$.