Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green BayXbr> First-time Visitors: Please visit Site Map and Disclaimer. Use "Back" to return here.

180/7 = 25.7 degrees, and tan (180/7) = 0.481. Arctan(0.5) = 26.6 degrees, less than a degree difference. This fact suggests a simple approximation.

Start with a square sheet folded diagonally in half. |

Fold the two bottom corners together |

Unfold the paper. |

Fold the paper lengthwise in half |

Unfold the paper. |

A diagonal of one quarter of the paper is a good approximation to 180/7 degrees. |

Fold the paper up along the diagonal |

Then fold the corner flat again. |

Fold the paper so the left half of the base coincides with the diagonal crease. The upfolded left edge makes an angle of 4(180/7) with the base. Bisect this angle twice to get 180/7 degrees. |

Here the angle is bisected once |

The final bisection |

Cut the wedge as desired and unfold it as shown below. |

A somewhat better approximation is to start the diagonal crease 1/4 of the way from the vertical center crease as shown. |

Below is the process animated |

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*Created 22 March 2006, Last Update
14 December 2009*