Answer:
We can determine if they are equivalent fractions if we find a number (or conversion factor) that when miltiplied by the denominator and the numerator of the original fraction results in the fraction that we want to know if it is equivalent.
original fraction:

if we multiply the numerator 1 and the denominator 3 by 4, we get:

we find that
is an equivalent fraction of 1/3 because we can find it by multiplying the numerator and denominator of 1/3 by the same number. In this case that number is 4.