1. Determine the total surface area in square meters of a grain silo with cylindrical shape with a conical roof. Diameter of the cylinder is 20 meters, the height of the cylinder is 15 meters from the ground, and height of cone is 4 meters from the top of cylinder. Total surface area shall include the base of cylinder (floor).
2. If the grain silo is made by assembling steel plates (each with an area of 7.2 square meters). How many plates are required to assemble the silo?