10 [Volume of pyramid= 1/3 ×base area × height] ABCDE is a rectangular-based pyramid. AC and BD intersect at F. EF is perpendicular to FC. AD = 10 cm, DC = 6 cm and EC = 12 cm. (a) Show that EF = 10.5 cm, correct to 1 decimal place. (b) Find the volume of the pyramid. (c) Calculate DECˆ . (d) Calculate the area of triangle DEC.