Question

Question 2
The triangular side walls of a flyover have been used for advertisements. The sides of the walls are 13m, 14m and 15m. the advertisements yield an earning of Rs.2000 per $m^2$ a year. A company hired one of its walls for 6 mnoths. How much rent did it pay?

Answer 1

Given that the sides of the triangular walls are
a = 13m, b = 14m and c = 15m
$\therefore$ semi-perimeter of triangular side wall,
$s=\frac{a+b+c}{2}$
$=\frac{13+14+15}{2}=\frac{42}{2}=21m$
$\therefore$ Area of triangular side wall $=\sqrt{s(s-a)(s-b)(s-c)}$ [by Heron’s formula]
$=\sqrt{21(21-13)(21-14)(21-15)}$
$=\sqrt{21\times 8\times 7\times 6}$
$=\sqrt{21\times 4\times 2\times 7\times 3\times 2}$
$=\sqrt{(21{)}^2\times (4{)}^2}=21\times 4=84m^2$
The advertisement yield earning per year for 1 $m^2$ = Rs. 2000
$\therefore$ The advertisement yield earning per year on 84 $m^2$ = 2000 $\times$ 84 = Rs.168000
As the company hired one of its walls for 6 months, therefore company pay the rent
$=\frac{1}{2}\left(168000\right)=Rs84000$
Hence, the company paid Rs.84000 as the rent.