Let x be the smaller natural number and y be the larger natural number. We know that:
x + y = 102 (equation 1)
y = 2x + 12 (equation 2)
Substituting equation 2 into equation 1, we get:
x + (2x + 12) = 102
Simplifying and solving for x, we get:
3x + 12 = 102
3x = 90
x = 30
Substituting x = 30 into equation 2, we get:
y = 2(30) + 12
y = 72
Therefore, the two natural numbers are 30 and 72.