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Ratio of 30-60-90 degree triangles

by Guest Fri Jun 20, 2008 6:41 pm

hi there,

Currently reading the geometry strategy guide on page 31 and don't fully get the following information.

Ratio is: 1: square root of 3: 2 for a 30-60 & 90 degree right angle triangle.

What I don't get is when a side is given for the hypotenuse (in this case 10) how do you find the multiplier based on the ratio provided. The ratio is 5: 5(square root of 3): 10.

Can anyone please shed some light on what I may be missing?

thanks!
guestt
 
 

by guestt Mon Jun 23, 2008 2:48 am

hi
i can help you find the other side by the unknown multiplier .
hi there,

In a 30-60-90 traingle the ration of sides is always this way
30-60 -90
1 - root 3 - 2
if the hypotenuese is given to be 10 means its is double of the side facing the 30 degree angle and for the side facing 60 degree angle it is divided by 10/root 3/2=5 root 3

this is how i goes
30-60 -90
1 - root 3 - 2

if for 1 it is 2
for 10 it is how much so cross multiply 10 * 1/2= 5
for root 3 it is 2
for 10 it is how much therefore cross multiply 10*root 3/2 = 5 root 3

hope that helps
rfernandez
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by rfernandez Fri Jun 27, 2008 2:56 am

I find it helpful to think of the ratio as 1x : root(3)x : 2x. If the hypotenuse is 10, then 2x=10, so the "multiplier" x is 5.

That means the side measures are 5 : 5*root(3) : 10.
Guest
 
 

by Guest Sun Jun 29, 2008 12:47 pm

Thanks Rey! That actually helped alot.
StaceyKoprince
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by StaceyKoprince Mon Jun 30, 2008 11:52 pm

Glad Rey could help!
Stacey Koprince
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Director, Content & Curriculum
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