The area of a rhombus is determined by the formula:
Area = $\dfrac{1}{2} \times d_1 \times d_2$
where $d_1$ and $d_2$ represent the lengths of the rhombus's diagonals.
Given: Area = 96 cm²
$\dfrac{1}{2} \times d_1 \times d_2 = 96$
Multiplying both sides by 2 yields:
$d_1 \times d_2 = 192$
The diagonals of a rhombus bisect each other perpendicularly. Therefore,
$\left(\dfrac{d_1}{2}\right)^2 + \left(\dfrac{d_2}{2}\right)^2 = 10^2$
This simplifies to:
$\Rightarrow \dfrac{d_1^2}{4} + \dfrac{d_2^2}{4} = 100$
Multiplying both sides by 4 results in:
$d_1^2 + d_2^2 = 400$
The identity used is: $(d_1 + d_2)^2 = d_1^2 + d_2^2 + 2d_1d_2$
Substituting the known values:
$(d_1 + d_2)^2 = 400 + 2 \times 192 = 400 + 384 = 784$
Taking the square root of both sides gives:
$\Rightarrow d_1 + d_2 = \sqrt{784} = 28$
The total length of wire needed for both diagonals is $d_1 + d_2 = 28$ meters.
The cost per meter is ₹125.
The total cost is calculated as: $28 \times 125 = ₹3500$
₹3500