Question

the triangular side walls of a flyover have been used for advertisement. the sides of the wall are 13 M 14 M 15 M the advertisements yield and earning of Rs 2000 per metre square a year . a company hired one of its wall for 6 month. how much rent pay

Answer 1

let s be semi perimeter and (a , b , c) be the sides of triangle
area of triangular wall = √s(s - a)(s - b)(s - c)
perimeter = 13 + 14 + 15 = 42 m 
semi peri. = 42 / 2 = 21 m 
area = √21(21 - 13)(21 - 14)(21 - 15)
= √21 * 8 * 7 * 6
= 7 * 2 * 3 * 2 = 84 m^2
cost of 84 m^2 = 2000 * 84 = 168000 rupees(whole year)
for 6 months = 1 /2 of 168000 = 84000 rupees