Cut the knot: learn to enjoy mathematics
A math books store at a unique math study site. Shopping at the store helps maintain the site. Thank you.
Learning Math Online
Sites for teachers
Sites for parents
Terms of use
Awards
Interactive Activities

CTK Exchange
CTK Wiki Math
CTK Insights - a blog
Math Help

III Millennium Olympiad

Games & Puzzles
What Is What
Arithmetic
Algebra
Geometry
Probability
Outline Mathematics
Make an Identity
Book Reviews
Stories for Young
Eye Opener
Analog Gadgets
Inventor's Paradox
Did you know?...
Proofs
Math as Language
Things Impossible
Visual Illusions
My Logo
Math Poll
Cut The Knot!
MSET99 Talk
Other Math sites
Front Page
Movie shortcuts
Personal info
Privacy Policy

Guest book
News sites

Recommend this site

Sites for parents

Education & Parenting

Manifesto  |  Bookstore  |  Contents  |  Amazon store  |  Term index  |  What changed?  |  Contact  |  Recommend
RSS Feed: Recent changes at CTK

Third Millennium International Mathematical Olympiad 2009
Grade 10-12
Problem 4

  By definition, the shortest pass between two points on the surface of a cube is the shortest broken line on the surface of the cube joining the two points. (Which is a straight line segment whenever the given points lie on the same face.) Three shortest passes joining three points split the surface of a cube into two regions. The region with the smallest area is called a triangle. Find the largest area of a triangle on the surface of a unit cube.

Solution by Carles Boix, Princeton, NJ, USA.

Copyright © 1996-2010 Alexander Bogomolny

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The maximum area will be achieved when both regions are equal. Therefore, the maximum area will be half of the surface area of the unit cube. Half of the surface area is 3 units².

Copyright © 1996-2010 Alexander Bogomolny

35694901Page copy protected against web site content infringement by Copyscape

Search:
Keywords:

Google
Web CTK