Answer :

Change 15/20 to 3/4
Now we have [tex] \frac{x}{6} = \frac{3}{4} [/tex]
multiply 6 to 3= 18 ÷ 4 = 4.5
x = 4.5
15/20 = 3/4
x/6 = 3/4
multiply 6 by 3
x = 18/4
x = 4.5