Given that, a = 8 cm, b = 10 cm and c = 12 cm We know, that s = (a + b + c)/2 = (8 + 10 + 12)/2= 30/2 = 15 cm ? (s - a) = (15 - 8) = 7 cm (s - b) = (15 - 10) = 5 cm (s - c) = (15 - 12) = 3 cm ? Area = ?s(s - a) (s - b) (s - c)= ?15 x 7 x 5 x 3= ?1575= ?25 x 63= 5?63 cm