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Squares in a pentagon | WildTrig: Intro to Rational Trigonometry | N J Wildberger

2,221 views · Published 24 May 2010 · 9:39 · Indexed 23 September 2026

Channel: Insights into Mathematics · 2010 · Science & Technology

We use rational trigonometry to solve a problem concerning a pentagon with inscribed touching squares---the question being to find the ratio of the sides of the pentagon to the squares, and also the ratios of two circles, one circumscribing the pentagon, the other inscribed in the squares.

The Golden spreads of WildTrig 25 play a key role, as they do for many problems with five fold symmetry.

This video is part of the WildTrig series, which introduces Rational Trigonometry and applies it to many different aspects of geometry.

Video Content
00:00 Introduction
2:22 One of the vertices of the pentagon
5:37 Geometry of the pentagon

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Squares in a pentagon | WildTrig: Intro to Rational Trigonometry | N J Wildberger

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