SOLUTION: The diagonal of a rectangle is 3 ft longer than the length of the rectangle and 4 ft longer than twice the width. Find the dimensions of the rectangle.

Algebra ->  Rectangles -> SOLUTION: The diagonal of a rectangle is 3 ft longer than the length of the rectangle and 4 ft longer than twice the width. Find the dimensions of the rectangle.      Log On


   



Question 1131622: The diagonal of a rectangle is 3 ft longer than the length of the rectangle and 4 ft longer than twice the width. Find the dimensions of the rectangle.
Found 2 solutions by MathLover1, ikleyn:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

if the diagonal d of a rectangle is 3 ft longer than the length L of the rectangle and 4 ft longer than twice the width W, we have
d=L%2B3
d=2W%2B4
=>L%2B3=2W%2B4
=>L=2W%2B4-3
=>L=2W%2B1

Find the dimensions of the rectangle:
we can only do this
L=2W%2B1
W=%28L-1%29%2F2
because neither perimeter nor area is given

Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
.
One equation is 

   L = 2W + 1,       (1)

as the tutor @LoverMath1 derived in her post.


The other equation is

    sqrt%28W%5E2+%2B+L%5E2%29 = 2W + 4.

which follows from the condition.


This second condition, due to (1), is the same as

    sqrt%28W%5E2+%2B+%282W%2B1%29%5E2%29 = 2W + 4.     (2)


Equation (2) is your basic equation to solve.   Square both sides

    W^2 + 4W^2 + 4W + 1 = 4W^2 + 16W + 16

    W^2 - 12W - 15 = 0.


Answer.  The dimensions of the rectangle are  W = %2812%2Bsqrt%28204%29%29%2F24  and  L = 2W+1 = %2848%2B2sqrt%28204%29%29%2F24 feet.