3. The diagram on the right shows a cube of side $18 \mathrm{~cm}$. A giant ant walks across the cube's surface from $\mathrm{X}$ to $\mathrm{Y}$ along the route shown. How far does it walk?
A $54 \mathrm{~cm}$
B $72 \mathrm{~cm}$
C $80 \mathrm{~cm}$
D $88 \mathrm{~cm}$
E $90 \mathrm{~cm}$
3. E From the diagram, the ant walks the equivalent of five edges. Therefore the ant walks $5 \times 18 \mathrm{~cm}=90 \mathrm{~cm}$.