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a rectangle has a length that is 2 less than 3 times the width of the area of rectangle is 16 find the dimensions and perimeter


Divya 25th Jun, 2020
Answers (2)
Soumili Majumdar 25th Jun, 2020
Help there,
Let's solve the problem:

Let, L and B be the length and breadth of the rectangle, respectively.
Now, given that,
L= 3B-2, and,
Area= L*B= 16 sq.unit

According to the given problem,
B(3B-2) = 16
or, 3B - 2B = 16
or, 3B - 2B - 16 = 0
or, 3B + 6B - 8B - 16 = 0
or, 3B (B+2) - 8 (B+2) = 0
or, (B+2) (3B-8) = 0

Now, B cannot be -2, since breadth cannot be negative.
Hence, B is 8/3, which is 2.6 unit.
L= 3B -2 = 6 unit.
Perimeter= 2 (L+B) = 17.2 unit.

Answer:
L= 6 unit.
B= 2.6 unit.
Perimeter= 17.2 unit.

Hope this answer helps you.
Thank you!!
Shivani Chaudhary 25th Jun, 2020

Hello!

Let the width(b) of the rectangle be 'x'.


Length, l = 3x - 2


Area of the rect. = l × b


16 = (3x - 2)*x


16 = 3x^2 - 2x


the equation is 3x^2 - 2x - 16 = 0


Now we will factorise this equation:-


3x^2 - 2x - 16


3x^2 - 8x + 6x - 16


3x^2 + 6x - 8x - 16


3x(x + 2) -8(x + 2)


(3x - 8)(x + 2)


Hence possible values of x can be 8/3 or -2.


Since the breadth can't be negative,


x = 8/3


Now, 3x - 2 = 3*(8/3) - 2


= 8 - 2 = 6 cm


Now, perimeter, P = 2(l + b)


P = 2(6 + 8/3)


P = 2(18 + 8/3)


P = 26/3 × 2


P = 52/3 cm


Hence the perimeter of the rectangle is 52/3 cm.


Thankyou!

Hope it helps!

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