/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 18 A cake is in the shape of a regu... [FREE SOLUTION] | 91Ó°ÊÓ

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A cake is in the shape of a regular hexagon with each of its sides exactly \(30 \mathrm{~cm}\) long. Seven flowers of icing adorn the top. Show that at least two flowers are not more than \(30 \mathrm{~cm}\) apart.

Short Answer

Expert verified
By the pigeonhole principle and the geometry of the hexagon, at least two flowers must be within 30 cm of each other.

Step by step solution

01

Understanding the Problem

We need to position seven flowers on a regular hexagonal cake where each side measures 30 cm. We want to demonstrate that at least two of those flowers must be no more than 30 cm apart.
02

Visualizing the Hexagon

A regular hexagon can be divided into six equilateral triangles, each with a side length of 30 cm. The distance between any two vertices of these triangles represents potential positions for the flowers, so these distances range from 0 to 60 cm.
03

Applying the Pigeonhole Principle

The hexagon has six vertices where flowers can be placed. Since there are seven flowers, we must place at least two flowers on the same line connecting any two vertices, by the pigeonhole principle. The maximum possible distance on such a line is the triangle side length (30 cm).
04

Final Conclusion

Since two flowers will inevitably share the same side (distance between hexagon vertices), they cannot be more than 30 cm apart. Therefore, it is guaranteed that at least two flowers are not more than 30 cm apart.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Hexagon Geometry
Hexagon geometry is fascinating because it combines simplicity with uniformity. A regular hexagon is a six-sided polygon where each side is equal in length. In our exercise, each side of the hexagon is exactly 30 cm long.

One interesting property of a regular hexagon is that it can be divided into six equilateral triangles. This characteristic helps us understand the geometry better. Because these triangles are equilateral, all their sides are equal, and their angles are always 60 degrees each.

When thinking about organizing things, like flowers on a hexagon-shaped cake, the symmetry and repeated patterns of a hexagon make it a perfect shape. It is these properties that we leverage to find solutions by considering the positions and distances between vertices, which are all evenly spaced.
Equilateral Triangles
Equilateral triangles are special because all three sides and all three angles are equal. They have a symmetry that simplifies many geometric calculations, especially when combined with other shapes like hexagons.

In this scenario, dividing the hexagon into six equilateral triangles allows us to easily visualize the placement of objects, such as flowers, around its perimeter. The side length of each triangle in our hexagon is 30 cm. This means that the maximum distance between two adjacent vertices (positions) is 30 cm, which becomes an important factor when using strategies like the Pigeonhole Principle.

Equilateral triangles are helpful because they ensure that the geometry around each vertex is consistent. This consistency is crucial when deducing properties about distances and positions. As each vertex and edge is part of the regular, predictable pattern, calculations remain simple and easy to follow.
Distance Calculation
When it comes to distance calculation in geometry, especially within polygons like hexagons, understanding the basics is essential. The primary idea is measuring the straight-line distance between two points, such as between two vertices of our hexagon.

In our exercise, because we have a regular hexagon divided into equilateral triangles, the maximum direct distance between any two adjacent vertices is the length of a triangle’s side, specifically 30 cm. By employing strategies such as the Pigeonhole Principle, we effectively utilize geometry to determine when and how these distances guarantee certain conditions.

The calculation and understanding of these distances are critical for spatial reasoning and for establishing relationships between objects placed within a geometric shape. Thus, being able to recognize the potential and limit of distances can lead to new insights and solutions, simplifying both theoretical and practical geometry tasks.

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