12. The diagram shows a rectangle $A B C D$ in which $A B=1$ metre and $A D=4$ metres. The points $E$ and $G$ are the midpoints of $A D$ and $A B$ and the points $F$ and $H$ are the midpoints of $A E$ and $A G$.

What is the area of the shaded rectangle?
A $\frac{1}{16} \mathrm{~m}^{2}$
B $\frac{1}{8} \mathrm{~m}^{2}$
C $\frac{1}{4} \mathrm{~m}^{2}$
$\mathrm{D} \frac{1}{2} \mathrm{~m}^{2}$
E $1 \mathrm{~m}^{2}$
12. $\mathrm{C}$

Since $E$ is the midpoint of $A D$ and $F$ is the midpoint of $A E$, the length of $F E$ is $\frac{1}{2} \times \frac{1}{2} \times 4 \mathrm{~cm}=1 \mathrm{~cm}$. Similarly, since $G$ is the midpoint of $A B$ and $H$ is the midpoint of $A G$, the length of $H G$ is $\frac{1}{2} \times \frac{1}{2} \times 1 \mathrm{~cm}=\frac{1}{4} \mathrm{~cm}$. Therefore the area of the shaded rectangle is $\left(1 \times \frac{1}{4}\right) \mathrm{cm}^{2}=\frac{1}{4} \mathrm{~cm}^{2}$.