Math, asked by sneha5555, 1 year ago

(60 Points)Be brainliest.....By answering this..I want step by step process..........I want No.38,39,40

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Answered by Anonymous
1

Here is your answers:

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38)

The length is 12 m more than breadth.

Let the breadth be x.

Length is 12 + x

Area is 4 * Perimeter

Area of a rectangle is l b...................(1)

Perimeter is 2 ( l + b ).................(2)

Area = 4 (Perimeter)

From 1 and 2:

==> l b = 4 * 2 ( l + b)

==> l b = 8 ( l +b )

But breadth is x and length is 12 + x

==> x ( 12 + x ) = 8 ( 12 + x + x)

==> 12 x + x ² = 8 ( 12 + 2 x)

==> 12 x + x² = 96  + 16 x

==> x² - 4 x - 96 = 0

==> x² - 12 x + 8 x - 96 = 0

==> x( x - 12 ) + 8(x-12 ) = 0

x =12 or x = 8

Length is 12 + x

==> 12 + 12 or 12 + 8

==> 24 or 20

But if l is 20 then it does not satisfy the condition.

So l must be 24 and b is 12 .

The dimensions are 24 m and 12 m

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39)

Perimeter is 2 ( l + b)

Given Perimeter is 68 m

2 ( l + b) = 68

==> l + b= 34 ...........................(1)

Diagonal = \sqrt { l^2 + b^2 } is given 26 m

==> Squaring both sides:

l² + b² = 26 ²

==> l² + b² = 676 .............................(2)

We know that (a+b)² = a² + b² + 2 a b

( l +b)² = 34² [From 1 ]

==> l² + b² + 2 l b = 1156

==> 676 + 2 l b = 1156 [From 2 ]

==> 2 l b = 480

==> lb = 480 / 2

==> l b =240 m²

The area is 240 m²

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40)

Let the side of the square be x.

Length of rectangle is 12 + x

Breadth of rectangle is 8 + x

The area of rectangle is twice of the square.

The area of square is x²

Area of rectangle is ( 12 + x)(8 + x)

==>(12+x)(8+x)=2x²

==> x² + 12 x + 8 x + 96 = 2x²

==> -x² + 20 x + 96 = 0

==> x² -20 x - 96 =0

==> x² - 24 x + 4 x - 96 =0

==> x ( x - 24 ) + 4( x - 24 )=0

==>( x + 4 )(x - 24 )=0

x is either 24 or x is -4

but x cannot be negative.

x is 24

So the perimeter is 4 x

==> 4* 24

==> 96 cm

The area is 96 cm

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Hope it helps you





sneha5555: Thanku so much
Anonymous: welcome dear!
Answered by vipinsingh03
0

Answer:


Step-by-step explanation:

Here is your answers:


_____________________________________


38)


The length is 12 m more than breadth.


Let the breadth be x.


Length is 12 + x


Area is 4 * Perimeter


Area of a rectangle is l b...................(1)


Perimeter is 2 ( l + b ).................(2)


Area = 4 (Perimeter)


From 1 and 2:


==> l b = 4 * 2 ( l + b)


==> l b = 8 ( l +b )


But breadth is x and length is 12 + x


==> x ( 12 + x ) = 8 ( 12 + x + x)


==> 12 x + x ² = 8 ( 12 + 2 x)


==> 12 x + x² = 96  + 16 x


==> x² - 4 x - 96 = 0


==> x² - 12 x + 8 x - 96 = 0


==> x( x - 12 ) + 8(x-12 ) = 0


x =12 or x = 8


Length is 12 + x


==> 12 + 12 or 12 + 8


==> 24 or 20


But if l is 20 then it does not satisfy the condition.


So l must be 24 and b is 12 .


The dimensions are 24 m and 12 m


____________________________________________________


39)


Perimeter is 2 ( l + b)


Given Perimeter is 68 m


2 ( l + b) = 68


==> l + b= 34 ...........................(1)


Diagonal =  is given 26 m


==> Squaring both sides:


l² + b² = 26 ²


==> l² + b² = 676 .............................(2)


We know that (a+b)² = a² + b² + 2 a b


( l +b)² = 34² [From 1 ]


==> l² + b² + 2 l b = 1156


==> 676 + 2 l b = 1156 [From 2 ]


==> 2 l b = 480


==> lb = 480 / 2


==> l b =240 m²


The area is 240 m²


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40)


Let the side of the square be x.


Length of rectangle is 12 + x


Breadth of rectangle is 8 + x


The area of rectangle is twice of the square.


The area of square is x²


Area of rectangle is ( 12 + x)(8 + x)


==>(12+x)(8+x)=2x²


==> x² + 12 x + 8 x + 96 = 2x²


==> -x² + 20 x + 96 = 0


==> x² -20 x - 96 =0


==> x² - 24 x + 4 x - 96 =0


==> x ( x - 24 ) + 4( x - 24 )=0


==>( x + 4 )(x - 24 )=0


x is either 24 or x is -4


but x cannot be negative.


x is 24


So the perimeter is 4 x


==> 4* 24


==> 96 cm


The area is 96 cm


_____________________________________________________________________


Hope it helps you


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