Practice Shortest Path Intuition in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The minimum-length route connecting two points, whose form depends on the geometry of the underlying space.

On a flat surface the straight line is always the shortest path between any two points.

Example 1

medium
A river runs along the x-axis. Town A is at (2, 3) and town B is at (8, 5), both north of the river. A pumping station on the river at point P(x, 0) connects to both towns. Find x that minimises the total pipe length AP + PB.

Example 2

hard
What is the shortest path between two points in the Euclidean plane, and why? Then explain why the shortest path on the surface of a sphere is a great circle arc.

Example 3

easy
What is the shortest distance from point P(4, 3) to the origin? Justify that the straight line gives the minimum.

Example 4

hard
An ant on the surface of a unit cube wants to travel from vertex A = (0,0,0) to the opposite vertex B = (1,1,1) along the surface. What is the shortest surface path, and what is its length?