3.3 The areas of three plots of land are in the ratio $2 \frac{3}{4}: 1 \frac{5}{6}: 1 \frac{3}{8}$. It is known that 72 centners of grain more were harvested from the first plot compared to the second. Find the area of all three plots, if the average yield is 18 centners per hectare.
3.3 Let $x, y, z$ be the areas of the plots. Then $\frac{x}{y}=\frac{6}{4}, \frac{y}{z}=\frac{4}{3}$, from which $x=6 k, y=4 k, z=3 k$. According to the condition, $(6 k-4 k) \cdot 18=72$, from which $k=2$. Therefore, the total area of all plots is $x+y+z=2(6+4+3)=26$ (ha).

Omeem: 26 ha.