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The length of the rectangle is 3ft less than twice the width,and the area of the rectangle is 27ft^2,find the diameter

Respuesta :

Answer:

The dimensions of rectangle are:

  • width = w = 4.5 ft
  • length = l = 6 ft

Step-by-step explanation:

Let 'l' be the length and 'w' be the width of the rectangle

  • The length 'l' of the rectangle is 3ft less than twice the width 'w'.

so

[tex]l=2w-3[/tex]

Also, the area of the rectangle is 27ft^2.

[tex]A=27\:ft^2[/tex]

As the area of the rectangle has the formula:

[tex]\:A\:=\:l\times w[/tex]

so

[tex]27=\:l\times w[/tex]

so the equation becomes

[tex]27=\left(2w-3\right)\times \:w[/tex]

[tex]27=2w^2-3w[/tex]

[tex]2w^2-3w-27=0[/tex]

[tex]\left(w+3\right)\left(2w-9\right)=0[/tex]

if   [tex]ab=0\:\mathrm{then}\:a=0\:\mathrm{or}\:b=0\:\left(\mathrm{or\:both}\:a=0\:\mathrm{and}\:b=0\right)[/tex]

[tex]w+3=0\quad \mathrm{or}\quad \:2w-9=0[/tex]

[tex]w=-3,\:w=\frac{9}{2}[/tex]

as the width can not be negative, so

[tex]w=\frac{9}{2}=4.5[/tex] ft

As

[tex]l=2w-3[/tex]

[tex]l=2\left(4.5\right)-3[/tex]

[tex]l=9-3[/tex]

[tex]l=6[/tex]

So the dimensions of rectangle are:

  • width = w = 4.5 ft
  • length = l = 6 ft

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