11) What is the cross sectional area of a circular ring of D = 38 mm d = 32mm?

12) What is the area of a sector of a circle of radius 5 cm and its angle is 96 Degree?

13) What is the area of an ellipse if the major and minor axes are 5 cm and 3 cm respectively?

14) Find the total surface area of cube whose side is 25 cm.

15) Find the total surface area of a cast iron bar whose length, width and height are 20m, 15m and 12m.