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What are all the rules/laws of a cirlce with intercepting lines, like medians and all those things?

I dont understand when there's a cirlce and multiple lines crossing what all the rules are for the ratio's of the lines, I remember learning something was one third of something else ? But i dont remember specfically.

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Diane S. | Math and Chemistry Tutor. Test Prep: SAT/ACT, Praxis, ISEE and more!Math and Chemistry Tutor. Test Prep: SAT...
5.0 5.0 (1580 lesson ratings) (1580)

Hi Alexa.  Are you talking about the median of a triangle?  It is often discussed when the incenter of a circle inscribed in a triangle is discussed (the incenter is where the angle bisectors of the triangle intersect).  But that's not where the 1/3, 2/3 comes from.  The 1/3, 2/3 are the ratios of the segments when medians of a triangle intersect.  Medians are from a vertex to the midpoint of the opposite side.  I think that may be what you are referring to.

Hope that helps.


Roger B. | Math and Science Tutor Focused on Deeper UnderstandingMath and Science Tutor Focused on Deeper...
5.0 5.0 (114 lesson ratings) (114)

Hi Alexa,

I believe you're talking about the formulas that relate various segments of chords, secants, and tangents that intersect a circle and each other.  There are also formulas for angles between chords, secants and tangents in terms of the lengths of arcs of the circle.  You should be able to find all these in the chapter of your geometry book about circles.  


Vicki N. | Top International Teacher, English Foreign Language Certified (TEFL)Top International Teacher, English Forei...
5.0 5.0 (104 lesson ratings) (104)

Hi Alexa,

What is the problem you are trying to solve?  Is it related to volume of a sphere (geometry) or measuring degrees and radians of a circle (trigonometry)?  If you can be more specific in rewriting your question that will be helpful to us tutors.

Thank you!

Vicki N.