Question

The sides of a triangular field are 30 m , 72 m and 78m . What will the cost of levelling the field be at 10 paise per sq. metre

Answer 1

area of triangle
$\frac{1}{2} b \times l$
area
$= 3042 {}^{2}$
therefore
$10 \times 3042 = 30420paise = 304.2rupees$

Answer 2

Given :

The sides of a triangular field are 30 m , 72 m and 78m .

To Find:

What will the cost of levelling the field be at 10 paise per sq. metre

Solution:

a=72 m

b = 30 m

c = 78 m

Area of triangle =$\sqrt{s(s-a)(s-b)(s-c)}$

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

Substitute the values in formula:

$s=\frac{30+72+78}{2}$

s=90

Area of triangle =$\sqrt{90(90-72)(90-30)(90-78)}$

Area of triangle =1080

Cost of leveling field 1 sq,m, = 10 paisa

Cost of leveling field 1080 sq,m, = $10 \times 1080 =10800 paisa$

100 paisa = 1 rupee

10800 paisa = 108 rupees

So, the cost of levelling the field be at 10 paise per sq. metre is 108 rupees