A lamp is ^@ 29.7 \space m ^@ above the ground. A boy ^@ 77 \space cm ^@ tall walks away from the base of this post at a speed of ^@ 1.8 \space m/s^@. Find the length of the shadow of the boy after ^@ 9 \space seconds ^@.
A building is in form of a right circular cylinder and cone as shown in the picture. The radius of cone and cylinder is 4 meters. The height of cylinder and cone are 8 meters and 3 meters respectively. Find the outer surface area of the building. (Assume π =