difference of two line segments constructions by Garrett Quinn https://padlet.com/gtquinn21/teae8sjfo5g0 en-us 2017-01-25 02:42:09 UTC 2017-06-19 14:38:15 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Xmastree.png gtquinn21 https://padlet.com/gtquinn21/teae8sjfo5g0/wish/149211965
The distance PQ is still the difference between the two segment lengths. In arithmetic, this would result in a negative length, which does not exist in Euclidean geometry. Segments cannot have a negative length. 


So the precise definition of what this construction does is find the absolute value of a–b
The two vertical bars mean "absolute value" which is always positive, regardless of the way a–b comes out. This is why the construction is titled "Difference of two segments" – it is not quite the same as arithmetic subtraction.

]]> 2017-01-25 02:44:32 UTC https://padlet.com/gtquinn21/teae8sjfo5g0/wish/149211965 gtquinn21 https://padlet.com/gtquinn21/teae8sjfo5g0/wish/149211988 Start with two given segments a and b. |

1.  Mark a point P towards the left of the work area. |

2.  Draw a long line from P to the right.  |

3.  Set the compasses width to the length of the segment a.

(Note: We can use the given segments in any order.) |

4.  Without changing the compass width, place the point on P and make an arc across the line, creating point Q |

5.  Set the compasses width to the length of the segment b. |

6.  Without changing the compass width, place the point on Q and make an arc across the line to its left. |

Done. The segment PR has a length which is the difference between the lengths of a and b |
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]]> 2017-01-25 02:45:44 UTC https://padlet.com/gtquinn21/teae8sjfo5g0/wish/149212039 gtquinn21 https://padlet.com/gtquinn21/teae8sjfo5g0/wish/149212059 http://www.mathopenref.com/constdiffsegments.html]]> 2017-01-25 02:46:09 UTC https://padlet.com/gtquinn21/teae8sjfo5g0/wish/149212059 https://padlet.com/gtquinn21/teae8sjfo5g0/wish/176871527 2017-06-19 14:38:15 UTC https://padlet.com/gtquinn21/teae8sjfo5g0/wish/176871527