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The edges of a triangular board are 6cm,...

The edges of a triangular board are `6cm,8cm" and "10cm` .The cost of painting it at the rate of `9paise per `"`cm^(2)` is "

A

rupee 2.00

B

rupee 2.16

C

rupee 2.48

D

rupee 3.00

Text Solution

Verified by Experts

The correct Answer is:
B
(b) Since, the edges of a trianglular board are a = 6 cm, b=8 cm and c=10 cm.
Now, semi-perimeter of a triangular board.
`s=(a+b+c)/(2)`
`=(6+8+10)/(2)=(24)/(2)=12 cm`
`"Now, area of triangular board"=sqrt(s(s-a)(s-b)(s-c)`
`=sqrt(12(12-6)(12-8)(12-10)`
`=sqrt(12xx6xx4xx2)`
`=sqrt((12)^(2)xx(2)^(2)`
`=12xx2=24 cm^(2)`
Since, the cost of painting for area 1 `cm^(2)=rupee 0.09`
`therefore` Cost of paint for area 24 `cm^(2)=0.09xx24`=rupee 2.16
Hence, the cost of triangular board is rupee 2.16.
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