If 2/5 divided by blank = 4/5 what is blank

2/5 : x = 4/5

multiply both sides by x to get it out of the denominator.

2/5 = 4/5x

now divide each side by 4/5 to get x by itself.

2/5 : 4/5 = x

divide fractions by multiplying the reciprocal of the divisor.

2/5x * 5/4 = x

10/20 = x

1/2 = x

So 2/5 divided by 1/2 = 4/5