Airforce

Four aeroplanes of Airforce viz, A,B,C,D, started for a demonstration flight towards east. After flying 50 km planes A and D flew towards right, planes B and C flew towards left. After 50 km, planes B and C flew towards their left, planes A and D also towards their left. In which directions are the aeroplanes A, B, D, C respectively flying now?

An airforce plane is ascending vertically at the rate of 100km/h .If the radius of the earth is rkm, how fast is the area of the earth,visible from the plane,increasing at 3 minutes after it started ascending? Given that the visible area A at height h is given by A=2 pi r^(2)(h)/(r+h) .