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October 16, 2025, 04:45:44 pm
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Author Topic: Geometry  (Read 3524 times)  Share 

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Studyinghard

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Geometry
« on: July 05, 2010, 10:24:35 pm »
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The areas of two similar triangles are 144 and 81. If the base of the larger triangle is 30, what is the corresponding base of the smaller triangle.
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Whatlol

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Re: Geometry
« Reply #1 on: July 05, 2010, 11:59:16 pm »
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Is it 22.5 by any chance?
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Whatlol

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Re: Geometry
« Reply #2 on: July 06, 2010, 12:08:52 am »
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I suppose i should put the workings out in then...
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Whatlol

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Re: Geometry
« Reply #3 on: July 06, 2010, 12:32:48 am »
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Quote from: cherylim23 on July 06, 2010, 12:07:11 am
^ Yeah it is.

Using similar areas, the fraction of the LENGTH of the larger: smaller = square root (144/81) = 12/9 = 4/3
30/4 x 3 = 22.5 :)

cbs using latex. :P

oh my god.. the way i did it was alot more complicated.. i got an expression for the base of the smaller triangle then substituted  b1/h1 x h2 = b2 into the equation for area 81= 0.5 30h^2/9.6 then rearranged that to get 81x19.6/30 = h^2 then substituted h=7.2 into b= 30x7.2/9.6 = 22.5 hahaha oh dear.
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Studyinghard

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Re: Geometry
« Reply #4 on: July 06, 2010, 12:58:16 pm »
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An inverted right circular cone of capacity 100m^3 is filled with water to half its depth. Find the volume of the water.
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TyErd

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Re: Geometry
« Reply #5 on: July 06, 2010, 03:29:01 pm »
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Studyinghard

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Re: Geometry
« Reply #6 on: July 08, 2010, 06:14:46 pm »
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A yacht starts from L and sails 12km due east to M. It then sails 9km on a bearing of 142 degrees to K. Find the magnitude of MLK.
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Studyinghard

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Re: Geometry
« Reply #7 on: July 08, 2010, 06:39:09 pm »
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Answer is in degrees.

And isnt the LMK angle 142 deg? :S

does your diagram look like my attachment?
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TyErd

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Re: Geometry
« Reply #8 on: July 11, 2010, 01:22:06 pm »
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I got an answer of 22
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TyErd

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Re: Geometry
« Reply #9 on: July 11, 2010, 01:59:38 pm »
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This was the diagram I had. You can first use cosine rule to find the third side and then use sine rule to find 
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