Please help me on how to solve diz XD

"A block of Granite is in the form of the frustum of a regular square pyramid whose upper and base lower base edges are 3ft and 7ft.., Respectively, if each of the lateral faces is inclined at an angle of 62^{o}30' to the base , Find the volume of the granite in block"

as seen on the book "Solid Mensuration By Kern And Bland 2nd Edition" #9 page 71

Thanks in advance !!