Answer:
For the triangle: length = 24ft, width = 6ft.
For the rectangular mat: length = 18ft, width = 4ft.
Step-by-step explanation:
A triangular flag is 4 times as long as its width, meaning
[tex]l = 4w[/tex],
and the area of the this flag is 72 square feet, which means
[tex]A =\dfrac{lw}{2} = \dfrac{w(4w)}{2}=72ft^2[/tex]
solving for width [tex]w[/tex] we get:
[tex]w = \sqrt{\dfrac{72}{2}},[/tex]
[tex]\boxed{w = 4\: feet}[/tex]
which gives a length of
[tex]l= 4w = 4*6ft[/tex]
[tex]\boxed{l= 24\: feet.}[/tex]
Similarly, rectangular mat is 14 feet longer than its width, meaning
[tex]l_1 = w_1+14[/tex]
and its area is 72 square feet which means
[tex]A = l_1w_1 = (w_1+14)w_1 = 72ft^2[/tex]
simplification gives
[tex]w_1^2+14w_1-72=0[/tex]
which we solve using the quadratic formula to give
[tex]\boxed{w_1= 4ft}[/tex],
[tex]w_1 = -18ft[/tex],
and since the width cannot be a negative number, we choose [tex]w_1= 4ft[/tex] as our answer.
Thus, the length of the rectangular box is
[tex]l_1 = w_1+14 = 4+14\\\\ \boxed{l_1 = 18\: feet.}[/tex]
To summarize, the length and the width of the triangular flag is 24 and 6 feet respectively, and for the rectangular box it is 18 and 4 feet respectively.