Clint carves these two similar trapezoids out of wood. The lengths of the bases of the trapezoids are given in inches. How many inches long is the top base of the lower trapezoid?

There is not enough information given to determine the length of the top base of the lower trapezoid. The lengths of the bases of the trapezoids and the angles of the trapezoids would be needed in order to calculate the length of the top base of the lower trapezoid.