[填空题]
The following cumulative frvj56obve l w-7equency diagg c8drsi9q d*b94v;bn ram shows the distance students need to travel to gegsri9*qbdn v9;db4c 8t to school.
1. Find the median distance a student travels to school.
2. Find the number of students that travel between 2 $\mathrm{~km}$ and 4 $\mathrm{~km}$ to get to school.
3. Find the percentage of students that travel more than 4.5 $\mathrm{~km}$ to get to school. %