Show that the ratios 10/20 and 30/60 from a proportion by finding a common multiplayer. show that the ratios are equal by writing them in simplest form.

5 can go into 10 and 20 so you just want to divide them by five which gives you 
2/4.

its still not simplified yet so 2 can go in to 2 and 4 so we divide them your answer should be 1/2

so your simplified answer for 10/20 is 1/2

so 10/20=1/2

same thing for 30/60

10 can go into 30 and 60 so we divide them by 10

you should get 3/6

its still not simplified 

3 can go into 3/6 so we divide them by 3

you should get 1/2

 so 30/60= 1/2

10/20 = 1/2. 

30/60 = 1/2

so your simplified answer for both of them is 1/2

I hope this helped!