Asand box measures 10 feet long by 8 feet wide by 1 foot deep what area of land must be clearest

What do you mean by "What area of land must be clearest?" Do you mean what land is needed to be cleared? Or how much is needed to fill it up? If that's the case it's 80^3 ft

point a is the center of the circle that passes through points e, f, and g and the center of the circle that passes through points x, y, and z.