Final answer:
To find an equivalent fraction for 3/7 with a denominator of 28, multiply both the numerator and the denominator of 3/7 by 4 to get 12/28.
Step-by-step explanation:
To write an equivalent fraction of 3/7 that has a denominator of 28, you need to find a number you can multiply both the numerator and the denominator by to achieve the new denominator. In this case, to obtain a denominator of 28, you multiply the original denominator, 7, by 4 because 7 times 4 is 28. You must do the same to the numerator, so you also multiply 3 by 4. Therefore, the equivalent fraction with a denominator of 28 is 12/28.