building a lighthouse out of wood

[kj]

can anybody tell me the best way to cut the compound angles i need to make a hexagonal shaped lighthouse.the lighthouse will be 5 feet in height.the wooden pieces will be 6 inches at the bottom and tapered to 3 inches at the top.i just dont know how to cut the angles or what the degrees i will need to make this shape.hope ive given enough info for someone cleverer than me to work this ous.any help would be brill.thanks....