A rectangular carport has an area 28 square feet. The height of the carport is 1 feet less than 2 times its length. Find the height and the length of the carport.

Respuesta :

Answer:

Dimension= [tex](4\times 7)\ feet[/tex]

Step-by-step explanation:

Given: Area of Carport= 28 feet²

           The height of the carport is 1 feet less than 2 times its length.

Lets assume the length of Carport be "w"

∴ Height of carport= [tex](2w-1)\ feet[/tex]

We know, Area of rectangle= [tex]width\times length[/tex]

∴[tex]28= w\times (2w-1)[/tex]

Using distributive property of multiplication.

⇒ [tex]28= 2w^{2} -w[/tex]

Subtracting both side by 28.

⇒ [tex]2w^{2} -w-28= 0[/tex]

Using the quadratic formula to solve the equation.

⇒ [tex]2w^{2} -w-28= 0[/tex]. what are the values of w.

Solving by using quadratic formula.

Formula: [tex]\frac{-b\pm \sqrt{b^{2}-4(ac) } }{2a}[/tex]

∴ In the equation [tex]2w^{2} -w-28= 0[/tex] , we have a= 2, b= -1 and c= -28.

Now, subtituting the value in the formula.

= [tex]\frac{-(-1)\pm \sqrt{(-1)^{2}-4(2\times -28) } }{2\times 2}[/tex]

= [tex]\frac{1\pm \sqrt{1 - 4(-56) } }{4}[/tex]

Opening parenthesis.

= [tex]\frac{1\pm \sqrt{1+224 } }{4}[/tex]

= [tex]\frac{1\pm \sqrt{225}}{4}[/tex]

We know 15²=225

= [tex]\frac{1\pm \sqrt{15^{2}}}{4}[/tex]

we know √a²=a

= [tex]\frac{1\pm 15 }{4}[/tex]

Now we have two solution

= [tex]\frac{16}{4} \ or\ \frac{-14}{4}[/tex]

Ignoring negative base or width or carport

∴ w= [tex]\frac{16}{4} = 4[/tex]

Hence, Length of carport is 4 feet

next subtituting the value of length to get height of carport

Height of carport= [tex](2w-1)\ feet[/tex]

⇒ Height of carport= [tex](2\times 4-1)[/tex]

⇒ Height of carport= [tex]7\ feet[/tex]

Hence dimension of rectangular carport= [tex](4\times 7)\ feet[/tex]