Question

triangular Park has 3side 120 metre 80 metre and 50 metre a gardener has to put a fence all around it and also plant grass inside how much area does he need to plant find the cost of fencing it with barbed wire at the rate of rupees 20 per metre leaving a space 3Metre for a gate on one side

Answer 1

Area to be fenced is 247 metres

So,
Cost of fencing is :-

$247 \times rs.20 = rs.4940$




Area in which grass will be planted is :-

$375 \sqrt{15} metres$


Please refer the above photograph for the used process.




KEY POINTS TO REMEMBER :-


☸️ Perimeter of Triangle is equal to
$a + b + c$
Where a, b and c are the respective sides of the triangle.



☸️ Area of scalen triangle by Heron's Formula :-

HERON'S FORMULA FOR AREA OF TRIANGLE

$\sqrt{s(s - a)(s - b)(s - c)}$

Where s is the semi perimeter of the triangle and a, b and c are the sides of the triangle.



☸️ Semi perimeter is the half of the perimeter of the triangle.
Algebrically :-

$s = \frac{perimeter}{2} = \frac{(a + b + c)}{2}$




Thanks!