Math Is Fun Forum

brainless_helpneed

Guest

Locus

Ok the question is A and B are two points 6 cm apart.Draw a diagram to show the region which is 4cm or less from A and 3cm or less from B.

please help me on this question

luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: Locus

how precise does youre drawing have to be? are you allowed to simply continue an existing line to extend it, or are you required to use a precise drawing point of reference when drawing lines?

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luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: Locus

wait, i though you wanted something far more complex:

this is how you would do it:

measure a distance along line of 4 cm from A, then make a circle with compasses about A, that passes through this point.
mesure a distance along line of 3 cm from B, then make a circle with compasses about B, that passes through this point.
the region where the circles overlap is the region where it is <= 4cm from A AND <= 3cm from B

(Take a look at flash movie for how i construct it)

http://denvish.net/ulf/1166032679_region.php

Last edited by luca-deltodesco (2006-12-13 05:58:10)

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MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,711

Re: Locus

luca ...

... well done!

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mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Locus

Ooh, nice. You made a flash movie to help explain an answer. Lots of extra points for that.

That's an interesting locus it makes. Kind of like a lens.

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Stanley_Marsh

Member

Registered: 2006-12-13

Posts: 345

Re: Locus

I think you sould draw two circles , with the radius 4 m, and 3 m, then the intersection of the two is what you need

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