2 1per2 cm banding 1 1/4 cm

2 1/2 cm : 1 1/4 cm
= 5/2 : 5/4
= (5/2 : 5/2) : (5/4 : 5/2)
= (5/2 x 2/5) : (5/4 x 2/5)
= 1 : 1/2

2[tex] \frac{1}{2} [/tex] : 1[tex] \frac{1}{4} [/tex]     = 5/2 : 5/4
               = (5/2 x 2/5) : (5/4 x 2/5)
               =  1 : 0.5