饼图显示了莉莉安上个月的开支。她把一半的钱花在了食物上。她在交通上花了多少钱？

1. Determine the percentage of expenditure on Entertainment

The sector for Entertainment has a right angle ($90^\circ$).
Percentage for Entertainment = $\frac{90^\circ}{360^\circ} \times 100\% = 25\%$.

2. Determine the percentage of expenditure on Books

Total percentage is $100\%$.
Food is half, which is $50\%$.
Percentage for Books = $100\% - 50\% \text{ (Food)} - 15\% \text{ (Transport)} - 25\% \text{ (Entertainment)} = 10\%$.

3. Find the total expenditure

We know $10\%$ of the total expenditure is $\char36{}80$.
$1\%$ of the total expenditure = $\frac{\char36{}80}{10} = \char36{}8$.
Total expenditure ($100\%$) = $\char36{}8 \times 100 = \char36{}800$.

4. Calculate the expenditure on Transport

Expenditure on Transport = $15\%$ of total expenditure.
Transport = $15 \times \char36{}8 = \char36{}120$.