Name an equivalent ratio for 1/2 with a denominator of 20

To begin with, equivalent fractions represent the same part of a whole number. So I need to find a fraction, with a denominator of 20, that is the same value as 1/2: 
1/2 = ?/20
1*10/2*10 = 10/20

Since the denominator needed to be 20, I multiplied the numerator and the denominator (1/2) by 10 to get 10/20. So, 1/2 and 10/20 are equivalent.