Find the area of a triangle whose sides measure 13 cm, 14 cm and 15 cm.  Choose the most appropriate option:
A) 72 B) 21 C) 84 D) 53 E) 18
Sol. Let a = 13, b = 14 and c = 15. Then, S = (1/2)(a + b + c) = 21.   (s- a) = 8, (s - b) = 7 and (s - c) = 6.   Area = (s(s- a) (s - b)(s - c)^(1/2) = (21 *8 * 7*6)^(1/2) = 84 cm^2.   Ans: 84
<result>C</result>
Find the area of a triangle whose sides measure 13 cm, 14 cm and 15 cm.