The length of a rectangle is 5ft more than twice its width, and the area of the rectangle is 88ft. How do you find the dimensions of the rectangle?

2 Answers
Jun 23, 2016

Length=16=16 feet, Width=11/2=112 feet.

Explanation:

Let the length & width be ll feet, & ww feet, rep.

By what is given, l=2w+5................(1).

Next, using the formula : Area of rectangle = length xx width, we get another eqn.,
l*w=88, or, by (1), (2w+5)*w=88, i.e., 2w^2+5w-88=0.

To factorise this, we observe that 2*88=2*8*11=16*11, & 16-11=5.

So we replace, 5w by 16w-11w, to get,

2w^2+16w-11w-88=0.

:. 2w(w+8)-11(w+8)=0.

:. (w+8)(2w-11)=0.

:. w = width=-8, which is not permissible, w=11/2.

Then (1) gives, l=16.

It is easy to verify that the pair (l,w) satisfies the given conds.

Hence the dimensions of the rectangle are length=16 feet, width=11/2 feet.

Jun 23, 2016

Length of rectangle is 16ft and Width is 5.5ft

Explanation:

The area of the rectangle should be 88 sq.ft in place of 88 ft mentioned in the question.
Let the width of the rectangle be x :. the length will be 2x+5 :.Area of rectangle is (2x+5)*x =88 or 2x^2+5x-88=0 or 2x^2+16x-11x-88=0 or 2x(x+8)-11(x+8) =0 or (2x-11)(x+8)=0 :. x= 5.5 or x=-8 Width cannot be negative So x=5.5 ; 2x+5=16 Hence length is 16ft and Width is 5.5ft[Ans]