# Can you solve this pier puzzle? | Summary and Q&A

376.5K views
July 20, 2016
by
Physics Girl
Can you solve this pier puzzle?

## TL;DR

The video explains how to find the shortest path from one town to another by using geometry and reflections.

## Key Insights

• 🏛️ The stingy city council wants to build a pier between two towns, Mordor and Hogsmeade, using as little material as possible.
• 🍰 Both intuitive approaches and mathematical equations can be used to find the shortest path, but the video focuses on a geometric approach.
• 🍰 By reflecting one town across the shoreline and finding the shortest distance between it and the other town, the optimal location for the pier can be determined.

## Transcript

[MUSIC PLAYING] Welcome to this brainteaser. So there are two towns. One we're going to call Mordor. And one we're going to call Hogsmeade. We want to build a pier on the shore between the two towns. But the stingy city council wants to use as little material as possible. So how do we minimize the path from Mordor to the pier and onto Hogsmeade? So... Read More

## Questions & Answers

### Q: How does the video suggest minimizing the path from Mordor to the pier and onto Hogsmeade?

The video suggests using geometry and reflections to find the shortest path. By reflecting one town across the shoreline and finding the shortest distance between it and the other town, the optimal location for the pier can be determined.

### Q: Can more advanced mathematical concepts be used to solve this problem?

Yes, the video mentions that calculus can be used to write the distances as a function of each other and minimize them. However, the video emphasizes the elegance and simplicity of the geometric approach.

### Q: How can a string and pin be used to find the optimal location for the pier?

By anchoring the pin at different points on the shoreline and wrapping the string around it, one can determine where the most string comes out on the side of the other town. This would indicate the location that minimizes the distance.

### Q: Why is geometry considered an essential tool in solving this problem?

Geometry provides the necessary tools to analyze the relationships and distances between the towns and the shoreline. By using geometric concepts such as reflections and similar triangles, the shortest path can be determined.

## Summary & Key Takeaways

• The video discusses the problem of building a pier between two towns, Mordor and Hogsmeade, and finding the shortest path between them.

• It explores different approaches to solving the problem, including setting up equations and using reflections and geometry.

• The video concludes that the shortest path is achieved by placing the pier at a specific location that minimizes the distance between the towns.