Answers

2015-03-07T11:57:45+05:30
Area=168 cm²
diagonal=25 cm
let length of the rectangle is x
bredth is y

then use Pythagorean theorem
x²+y²=25²
625=x²+y²
y²=625-x²...(1)
area(168)=x*y
168²=x² * y²
28224= x² * y²

we know y²=625-x²
then
x²(625-x²)28224
 -x^{4} +625 x^{2} =28224 \\ 

multiply the whole equation with (-1)

then
 x^{4} -625 x^{2} = -28224

we want to write this formula in (a-b)² type..
let a=x²,,,2ab=625x²
so we will get 2b=625
b=312.5

add (312.5) in two sides of the formula

 x^{4} +312.5 ^{2} -625x= -28224+(312.25)^{2}  \\  \\ &#10;( x^{2} -312.5) ^{2}= 97656.25- 28224=69432.25 \\  \\ &#10;  x^{2} -312.5= \sqrt{69432.25} =263.50 \\ &#10; x^{2} =312.5+263.5=576 \\ &#10; x^{2} =576 \\ &#10;x= \sqrt{576} =24 \\<strong> &#10;</strong>length=24 \\ &#10;area=168 \\ &#10;length*bredth=168&#10;\\ bredth=168/24=7 cm\\  perimeter=2(length+bredth)&#10;=2(24+7)=62 cm



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2015-03-07T14:48:34+05:30
L*b=168
l^{2} *b^{2} =168 ^{2} =28224
l ^{2} +b ^{2} =[tex]25 ^{2} =625
l ^{2} =625 -b ^{2}
l ^{2} (625-l ^{2})=28224
625l ^{2} -l^{4} =28224
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sry..i cant complete this..there is mistake in continuous
do u want help??\
yes,i didnt get value of l by factorising