A triangular plot of land has the shape of a right triangle with legs of length units and units. In the corner where those sides meet at a right angle, a small uncultivated square is left, such that from an aerial view it resembles the right angle symbol. The rest of the land is cultivated. The shortest distance from the outer vertex of square (the vertex not on the legs of the triangle) to the hypotenuse is units. What fraction of the land is cultivated?
