Pogledati priloženi dijagram.
Stranicu kvadrata obeležićemo sa
![](https://static.elitesecurity.org/tex/64d3dae627ebefd097b7916f8bdc6826.png)
. Tačke
![](https://static.elitesecurity.org/tex/6cdbee8742bbb6cafdeedb9f9050570b.png)
i
![](https://static.elitesecurity.org/tex/633f34a51bdb3995281b09f7d86d590a.png)
su presečne tačke prave
![](https://static.elitesecurity.org/tex/be237a2c608767dba3b6e8fc9087911c.png)
s pravama
![](https://static.elitesecurity.org/tex/79ad9621e54b2b71514ece5721db342b.png)
odnosno
![](https://static.elitesecurity.org/tex/5532e3271ab32eefd99cb2241f62e437.png)
.
Nadalje imamo
![](https://static.elitesecurity.org/tex/f5136df933ff14e902889b85c9e38a9b.png)
- uglovi
![](https://static.elitesecurity.org/tex/8ae3395bff6661726bfa69d82ba8e372.png)
i
![](https://static.elitesecurity.org/tex/bc5660cbb08c446f7f21dde1cbefdbc9.png)
su pravi, uglovi
![](https://static.elitesecurity.org/tex/3202095f5dd38e1bc9cf69851cca5a6c.png)
i
![](https://static.elitesecurity.org/tex/f858762240daea629b1bb3115b983b07.png)
su unakrsni, a
![](https://static.elitesecurity.org/tex/6421b45184e7864c99a7ef616c8cb895.png)
. Stoga je
Potom je
![](https://static.elitesecurity.org/tex/5050c157e67c7685fac9b01e23cc7f45.png)
jednakokrak, jer je
![](https://static.elitesecurity.org/tex/072a964bf6bf2ecaaf3d7e7d187ccc0b.png)
, pa je
![](https://static.elitesecurity.org/tex/0cfd77ed917ff2a7556fc1afe6bac278.png)
i
![](https://static.elitesecurity.org/tex/2a2f1e2be5a6fd7bf62d9fe457ba931d.png)
. Međutim
Stoga dobijamo jednačinu
![](https://static.elitesecurity.org/tex/e21d98d574c34b90b7bfaa6c1407277c.png)
. Rešavanjem, i uzimanjem rešenja koje je manje od
![](https://static.elitesecurity.org/tex/64d3dae627ebefd097b7916f8bdc6826.png)
, dobijamo
![](https://static.elitesecurity.org/tex/a15e9acdbd5034a1495c5d8e660a02f8.png)
.
Iz toga sledi
![](https://static.elitesecurity.org/tex/58fc86bed8a70ee2fa6b01284225d0a1.png)
. Prema tome, u pravouglom trouglu
![](https://static.elitesecurity.org/tex/8ae3395bff6661726bfa69d82ba8e372.png)
katete se odnose kao
![](https://static.elitesecurity.org/tex/542869e0b9abcc713c72f98b09e96b60.png)
, što znači da je
![](https://static.elitesecurity.org/tex/b9d3d110161f1886f5120eee2d2834b6.png)
, te je konačno
[Ovu poruku je menjao Farenhajt dana 11.05.2010. u 07:41 GMT+1]