# Did you know that a right triangle can be found using only one side?

1. Apr 23, 2013

### Crazy Horse 11

I have found a way to find right triangles using only one side.

How do I show you without being deleted?

2. Apr 23, 2013

### dx

You can construct many different right triangles, from a given one side. You cannot post claims or theories here that contradict accepted results, but you can probably get away with a post along the lines of "here are my thoughts, is there something wrong with the way I am thinking?"

3. Apr 23, 2013

### Crazy Horse 11

Yes but how do you know what their values are? My formula finds the values of the triangle using only the one side.

Here is my formula: c^2 = cx + cy what is wrong with it when the line c = x + y? For example:

c = 1.8 + 3.2 = 5. This line = 5 is made up of two segments of x = 1.8 and y = 3.2.

The square root "sqrt" of c^2 is c. I can't write any more simply than this.

c^2 = cx + cy
c = sqrt (cx + cy)
5 = sqrt ((5*1.8) + (5*3.2))
5 = sqrt (9 + 16)
5 = sqrt 25
5 = 5
side c = 5
side a = sqrt (c^2 - cy) = sqrt cx = sqrt 9 = 3
side b = sqrt (c^2 - cx) = sqrt cy = sqrt 16 = 4

4. Apr 23, 2013

### Fredrik

Staff Emeritus
x+y=5 is the equation of a line. There's a point on that line with coordinates x=1.8, y=3.2. But so what? It's still impossible to tell what triangle you're talking about.

The first six lines of your calculation are just a complicated way to rewrite 5=1.8+3.2 as 5=5. This doesn't prove anything about any triangle.

If the hypotenuse (longest side) of a right triangle is 5, it's possible that the other two sides are 3 and 4. That much is correct. But it's also possible that they are (for example) 1 and $2\sqrt 6$, because
$$1^2+(2\sqrt{6})^2=1+24=25=5^2.$$

Last edited: Apr 23, 2013
5. Apr 23, 2013

### dx

You have chosen to divide c (the hypotenuse) as x + y, and to each of the possible ways of dividing c into two parts, you have a right triangle.

You could have chosen c = 5 = 2.5 + 2.5, then you would get a = b = sqrt(5(2.5))

Last edited: Apr 23, 2013
6. Apr 23, 2013

### Fredrik

Staff Emeritus
For starters, you don't claim to have found something that contradicts mathematics. If I had seen the thread title and the first line of post #1 before I wrote my reply, I would have deleted the thread instantly.

7. Apr 23, 2013

### dx

A picture:

Last edited by a moderator: Apr 24, 2013
8. Apr 23, 2013

### Fredrik

Staff Emeritus
You're quite an artist dx.

I can't tell what the lower left symbol is.

Don't spend too much time on this thread. It will probably end up deleted anyway.

9. Apr 24, 2013

### Crazy Horse 11

That is correct. The point where x = 1.8 gives the height of the triangle which when using Pythagoras theorem yields a side of 2.4 see?

c=3
b=1.8
a^2 = c^2 - b^2
a^2 = 9 - 3.24
a^2 = 5.76
a = 2.4 note: the height of the triangle is 2.4 at the point x = 1.8 or y = 3.2 on the hypotenuse = 5

the point is that c = x + y at 5 = 1.8 + 3.2 is just an example of how c^2 = cx + cy works at finding the three sides of a right triangle. I could have said 5 = 2.5 + 2.5 or 5 = 1.3 + 3.7 etc...

5 = 1.3 + 3.7
25 = 6.5 + 18.5
side a = sqrt 6.5
side b = sqrt 18.5
side c = sqrt 25

The Spencer Triangle Method: c = x + y does not use angles or more than one side to find the other two sides for a right triangle. This is a totally new except that I have shown it on the internet before on other cites.

It is very discouraging to have original new math concepts deleted without much consideration here on this forum. Very simple concepts run very deep in thought. That is what a discussion is for frankly.

Because it doesn't seem to make sense to one mentor and then he wipes the board clean. What a waste of prime intelligence in a raw state. You throw away a nugget of pure gold because you didn't find a polished ring that fit your finger! That is the great downfall of this forum.

Already this forum has wiped away a formula for a rational pi because it didn't look pleasing to the eye. Too Bad you short sited ones! Why couldn't you discuss where the equation was flawed?

Because you thought that your intelligence was threatened? how cowardly of you.

Up until now only Pythagoras theorem found right triangles but now another method has been found namely c^2 = cx + cy. What is stopping you from deleting history now?.

10. Apr 24, 2013

### Crazy Horse 11

In reverse a 3, 4, 5 triangle is c^2 = a^2 + b^2. This is 25 = 9 + 16. 9/c = 1.8 and 16/c = 3.2. 1.8 + 3.2 = c. What a priceless discovery if I do say so myself.

11. Apr 24, 2013

### Crazy Horse 11

c = x + y would be 1/c = 0.2 for x and 24/c = 4.8 for y then the original line or side would be
5 = 0.2 + 4.8

12. Apr 24, 2013

### pwsnafu

This is trivial. All you have done is taken $c^2 = a^2 + b^2$ and divided both sides by c to obtain $c = \frac{a^2}{c} + \frac{b^2}{c}$. And then declared $x = \frac{a^2}{c}$ and $y = \frac{b^2}{c}$. So your formula is equivalent to Pythagoras.

Last edited: Apr 24, 2013
13. Apr 24, 2013

### Crazy Horse 11

Sorry but c = x + y equals only one line. From the knowledge of one line comes the other two sides c^2 = cx + cy. In fact Pythagoras requires two sides at least. But he found his method first in time. In fact his method is equivalent to mine. Sorry for the ego.

I can find a triangle without Pythagoras but can he find a triangle with only one side and no angles? I severely doubt it very much. This is by no means trivial. Simple yes but not trivial.

14. Apr 24, 2013

### Staff: Mentor

There is nothing new to your method. All you do is to choose the length of the hypotenuse (here: 5) plus one additional length in your triangle (here: 1.8). You use Pythagoras in an implicit way, as pwsnafu showed. You find three values c,a,b which satisfy c^2=a^2+b^2 by construction.

In the same way, you could directly choose another side length:
5 and 2 give sqrt(5^2-2^2)=sqrt(21) as third side.
5 and 3 give sqrt(5^2-3^2)=sqrt(16)=4 as third side.
...

15. Apr 24, 2013

### pwsnafu

Pythagoras cannot determine a triangle using only knowledge of one side.
Your method is equivalent to Pythagoras.
Therefore your method cannot determine a triangle using only knowledge of one side.

Do you why it doesn't work? Because if you only fix one side, there are an infinite number of triangles which satisfy it.

In order to solve anything, you are using knowledge of two sides. You just don't realise it.

16. Apr 24, 2013

### Crazy Horse 11

Basically you lie mathematically speaking. How many different right triangles can you make from
c = 0.2 + 4.8? You say that you can arrange an infinite amount and I say that you lie.
I have side c = 5 and side a = 1 and side b = 2 sqrt 6.

Show me just one other right triangle from c = 0.2 + 4.8. I don't think that you can.

17. Apr 24, 2013

### Staff: Mentor

c = 0.2+4.8 = 5

a2 + b2 = 52

$$a = \sqrt{25 - b^2}$$

Any b<5 you put into the equation has a corresponding a.

$$b = 1, a = \sqrt{24} = 2\sqrt 6\\ b = 2, a = \sqrt{20} = 2\sqrt 5\\ b = 3, a = \sqrt{16} = 4$$

Already three different solutions.

18. Apr 24, 2013

### Crazy Horse 11

I notice only one solution for c = 0.2 + 4.8. Even your third offering is still c = 1.8 + 3.2. You prove my point that there is only one right triangle for each c = x + y.

I will now ask you this. What are the three sides of the right triangle from c = 12.44578 + 8.17695? You already know that it only describes one right triangle don't you by now?.

19. Apr 24, 2013

### dx

Haha.. that's a pretty bad drawing.

The symbol is x. Here's a better drawing. One can show that the possible positions of the vertex of the triangle with the right angle must lie on a circle, with c as the diameter.

Here x + y = c and xy = h2

So we have

a2 = x2 + h2 = x2 + xy = xc

which implies a = √(xc)

Similarly b = √(yc)

Last edited by a moderator: Apr 24, 2013
20. Apr 24, 2013

### Staff: Mentor

If you are splitting c into two given parts, you are no longer speaking of a universal solution using ONE SIDE. Your are solving an entirely different question - what are catheti of a right triangle in which hypotenuse is split by the triangle height into x and y. And then yes, it is a trivial problem with a single solution.