Um, we see that the slice created the triangle, and the formula to find the area of the triangle: 1/2×B×h where B represent Base and h represent height. In this case, Base=5 cm Height=11 cm A=1/2×11×5 A=5.5×5 A=27.5 square cm. As a result, the area of the resulting two-dimensional cross section is 27.5 square cm. Hope it help!