SOLUTION: Given 30-60-90 triangle with sides p\sqrt(6) , p\sqrt(2 ), q\sqrt(3); find p, q

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Question 1205030: Given 30-60-90 triangle with sides p\sqrt(6) , p\sqrt(2 ), q\sqrt(3); find p, q

Found 2 solutions by greenestamps, ikleyn:
Answer by greenestamps(13206) About Me  (Show Source):
You can put this solution on YOUR website!


Don't use "\" -- it might have a special meaning in some area(s) of mathematics.

I assume the side lengths are p/sqrt(6), q/sqrt(3), and p/sqrt(2).

The squares of the side lengths are then p^2/6, q^2/3, and p^2/2.

On first glance, with the denominators 6, 3, and 2, I immediately see that, if p and q are both equal to the same number x, then I have x^2/6+x^2/3=x^2/2, which is true for all values of x.

So the problem has an infinite number of solutions in which p=q.

But there might be other solutions hiding somewhere, so lets' look at the problem more closely.

We know that p/sqrt(2) is greater than p/sqrt(6); but q/sqrt(3) could be less than or greater than p/sqrt(2). So there are two cases to consider: the longest side (hypotenuse) can be either p/sqrt(2) or q/sqrt(3).

Case 1: the hypotenuse is p/sqrt(2)

(Note this is the case discussed informally above.)

%28p%2Fsqrt%286%29%29%5E2%2B%28q%2Fsqrt%283%29%29%5E2=%28p%2Fsqrt%282%29%29%5E2
p%5E2%2F6%2Bq%5E2%2F3=p%5E2%2F2
p%5E2%2B2q%5E2=3p%5E2
2q%5E2=2p%5E2
p%5E2=q%5E2
p=q

Case 2: The hypotenuse is q/sqrt(3)

%28p%2Fsqrt%282%29%29%5E2%2B%28p%2Fsqrt%286%29%29%5E2=%28q%2Fsqrt%283%29%29%5E2
p%5E2%2F2%2Bp%5E2%2F6=q%5E2%2F3
3p%5E2%2Bp%5E2=2q%5E2
4p%5E2=2q%5E2
2p%5E2=q%5E2
p%2Asqrt%282%29=q

This case also has an infinite number of solutions, where p is any number x and q is x*sqrt(2).

ANSWER:
p = any number;
q = p OR q=p*sqrt(2)


Answer by ikleyn(52864) About Me  (Show Source):
You can put this solution on YOUR website!
.
Given 30-60-90 triangle with sides p/sqrt(6) , p/sqrt(2 ), q/sqrt(3); find p, q
~~~~~~~~~~~~~~~~~~~~~


        Notice that I rewrote the condition using normal designations for the division operation.


Two sides  p%2Fsqrt%282%29  and  p%2Fsqrt%286%29  have the ratio

    %28%28p%2Fsqrt%282%29%29%29%2F%28%28p%2Fsqrt%286%29%29%29 = sqrt%286%29%2Fsqrt%282%29 = sqrt%283%29.


In combination with the given fact that the triangle is 30-60-90, 
it means that  p%2Fsqrt%286%29  is  the shorter leg,  while  p%2Fsqrt%282%29  is  the longer leg.


    +-----------------------------------------------+
    |      It admits only one interpretation,       |
    |  and no other interpretation is admittable.   |
    +-----------------------------------------------+


Hence, q%2Fsqrt%283%29 is the hypotenuse, and we can write

    2%2A%28p%2Fsqrt%286%29%29 = q%2Fsqrt%283%29


(the hypotenuse length is twice the shorter leg), since the triangle is 30-60-90.


It gives  q = %282%2Ap%2Asqrt%283%29%29%2Fsqrt%286%29 = %282%2Fsqrt%282%29%29%2Ap = sqrt%282%29%2Ap.


So, the sides are:  p%2Fsqrt%286%29  is  the shorter leg,  p%2Fsqrt%282%29  is  the longer leg and  q%2Fsqrt%283%29 = %28sqrt%282%29%2Ap%29%2Fsqrt%283%29  is the hypotenuse.


We can write then Pythagorean equation

    %28p%2Fsqrt%286%29%29%5E2 + %28p%2Fsqrt%282%29%29%5E2 = %282%2F3%29%2A%28sqrt%282%29%29%5E2%2Ap%5E2,

or

    p%5E2%2F6 + p%5E2%2F2 = %282%2F3%29%2Ap%5E2,

    1%2F6 + 3%2F6 = 2%2F3,

    4%2F6 = 2%2F3,

    2%2F3 = 2%2F3,


which is an identity.


At this point, the problem is solved in full.


ANSWER.  p can be any real positive number; then q = sqrt%282%29%2Ap.  There are infinitely many solutions.

Solved.