Question

a rhombus shaped sheet with perimeter 40 cm and one diagonal 12 cm ,is painted on both sides at the rate of rs 5 per cm square . find the cost of painting.​

Answer 1

REFER ATTACHMENT ANS IS GIVEN

Answer 2

Answer:

The cost of painting is 960 Rupees.

Step-by-step explanation:

Let ABCD be a rhombus, then AB=BC=CD=DA=x

Perimeter of rhombus =40cm

$4x=40cm\\ \\ x=10cm$

$AB=BC=CD=DA=10cm$

In $\triangle ABC,S=\frac{a+b+c}{2} =\frac{10+10+12}{2} =16 cm$

Area of the rectangle,

           $ar. \triangle ABC=\sqrt{s(s-a)(s-b)(s-c)} =\sqrt{16(16-10)(16-10)(16-12)} \\ \\ =\sqrt{16 \cdot 6 \cdot 6 \cdot 4} =\sqrt{2 \cdot 2 \cdot 2\cdot2\cdot2\cdot3\cdot2\cdot3\cdot2\cdot2} \\ \\ =2\cdot2\cdot2\cdot2\cdot3=48$

Area of ABCD=2×48=96cm²

Cost of painting the sheet =Rs(5×96×2)=Rs960 [Both sides]