A rhombus shaped sheet with perimeter 40 cm and one diagonal is 12 cm, is painted on both sides at the rate of rs.5 per m sq. find the cost of painting. need the answer fast. pls help

let ABCD be a rhombus,

perimeter = 40

so, AB=BC=CD=DA=10

let diagnols ACBD intersect at O

so let BD =12

or BO=6so in trangle AOB

AB^{2}= AO^{2}+OB^{2}

AO^{2}=10^{2}-6^{2}

AO^{2}=64

AO=8

AC=16

so area of rhombus is 1/2*d_{1}*d_{2}

ar ABCD = 1/2*12*16

=96cm^{2}

total area of both sides = 192 cm^{2}

cost of painting 1 m^{2} = Rs 5

cost of painting 10000 cm^{2} = Rs 5 (1m sq = 10,000 cm sq)

cost of painting 1 cm^{2} = Rs 5/10000

cost of painting 192 cm^{2} = Rs 5/10000 * 192

cost of painting 192 cm^{2} = Re 0.096

it will cost 9.6 paise for painting both the sides of rhombus

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