Đặt AB = BC = CD = a, ta có:

• $\frac{{AB}}{{BD}} = \frac{{AB}}{{BC + CD}} = \frac{a}{{a + a}} = \frac{a}{{2a}} = \frac{1}{2}$;

• $\frac{{AB}}{{AD}} = \frac{{AB}}{{AB + BC + CD}} = \frac{a}{{a + a + a}} = \frac{a}{{3a}} = \frac{1}{3}$;

• $\frac{{AC}}{{AD}} = \frac{{AB + BC}}{{AB + BC + CD}} = \frac{{a + a}}{{a + a + a}} = \frac{{2a}}{{3a}} = \frac{2}{3}$.