Alright so, I decided to read some Euclid's Elements for my own personal gain (became interested while reading Stewart's Precal, and I think it might help with Calculus) and I'm stuck on proposition 7, mainly because I really want to understand the reasoning behind it and I just can't seem to make a connection.(adsbygoogle = window.adsbygoogle || []).push({});

I pretty much understand the basis of what proposition 7 is trying to prove or demonstrate, but I just can't get around the fact that in the statement that "the angle ADC is greater than the angle DCB; therefore the angle CDB is much greater than the angle DCB" doesn't make sense to me. ADC is not equal to CDB.

Maybe I'm just too stupid to understand, but where is the assumption that angle CDB must be greater than DCB made plausible?

Here is the link to the proposition

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Euclid's Elements: Proposition 7

Loading...

Similar Threads - Euclid's Elements Proposition | Date |
---|---|

Euclid's elements book 3 proposition 20 | Jun 18, 2015 |

Horn angles and Euclid's elements | Jun 17, 2015 |

Euclid's elements proposition 15 book 3 | Jun 17, 2015 |

How to best read Euclid's Elements | Feb 27, 2015 |

Euclid's element (P14) | Jun 3, 2014 |

**Physics Forums - The Fusion of Science and Community**