She sees a place to get a burger across the park. I'm sure you've heard that the shortest distance between 2 points is a straight line. So Ana's going to cut diagonally across the park.
Calculating distance is tied to a famous theorem.
Read about it here . Ana's cutting across the park illustrates another theorem in - that in any triangle, any one side is less than the sum of the other two sides. Now look at the school bus to the left. If you talk about how far away the bus is from McDonald's, it's the same distance that Ana was. The school bus can't tear out across the park.