Question

What is an equivalent ratio for 5:13

Answer 1

You can multiply the top and the bottom with the same number to get a equivalent ratio
or

Just multiply 5:13 by any number
10:26
15:39
20:52
25:65
etc...

Answer 2

Find a number that both 5 and 13 go into, then take how many times 13 goes into that number and multiply 5 by that answer. The number you get is the answer (written a:b). 

13x5= 65    5x5=25    5:13= 25:65    (order matters!)