Question

52 is 130% of what number

Answer 1

52 divided by 130 would be 0.4 so if you need it in percent then it would be 4%.

Answer 2

Let x be that number. Then 
130% x = 52
>> (130/100) x = 52
>> 1.3 x = 52
>> x = 52 / 1.3

>> x = 40