Se define la razón de izquierda a derecha en los tres casos :
<img src="https://tex.z-dn.net/?f=r%3D%20%5Cfrac%7B%7CPQ%7C%7D%7B%7CQR%7C%7D%20" />
caso 1.
<img src="https://tex.z-dn.net/?f=r1%3D%20%5Cfrac%7B%289-8%29%2C%283-5%29%7D%7B%2812-9%29%2C%28-3-3%29%7D%20" />
<img src="https://tex.z-dn.net/?f=r1%3D%20%5Cfrac%7B%281%2C-2%29%7D%7B%283%2C-6%29%7D%20" />
aplicando modulo se obtiene la razón del primer caso
<img src="https://tex.z-dn.net/?f=r1%3D%20%5Cfrac%7B2.2%7D%7B6.7%7D%20" />
caso 2.
<img src="https://tex.z-dn.net/?f=r2%3D%20%5Cfrac%7B%2810-8%29%2C%281-5%29%7D%7B%2812-10%29%2C%28-3-1%29%7D%20" />
<img src="https://tex.z-dn.net/?f=r2%3D%20%5Cfrac%7B%282%2C-4%29%7D%7B%282%2C-4%29%7D%20" />
aplicando modulo se obtiene la razón del segundocaso
<img src="https://tex.z-dn.net/?f=r2%3D%20%5Cfrac%7B1%7D%7B1%7D%20" />
caso 3.
<img src="https://tex.z-dn.net/?f=3%3D%20%5Cfrac%7B%2811-8%29%2C%28-1-5%29%7D%7B%2812-11%29%2C%28-3%2B1%29%7D%20" />
<img src="https://tex.z-dn.net/?f=r3%3D%20%5Cfrac%7B%283%2C-6%29%7D%7B%281%2C-2%29%7D%20" />
aplicando modulo se obtiene la razón del tercer caso
<img src="https://tex.z-dn.net/?f=r3%3D%20%5Cfrac%7B6.7%7D%7B2.2%7D%20" />.