Let's first conceptualize the given details by drawing a rectangle with the given details being reflected.
Where,
x = Height of the rectangle
x + 71 = The ratio of the width of the rectangle with respect to the height.
Cutting the rectangle in half along the diagonal line makes a right triangle,
Thus, we can use the Pythagorean Theorem to be able to determine the height of the rectangle. We get,
[tex]\text{ a}^2+b^2=c^2\text{ }\rightarrow(x+71)^2+(x)^2=(81)^2_{}[/tex][tex]\text{ x}^2+142x+5041+x^2\text{ = 6561}[/tex][tex]\text{ 2x}^2\text{ + 142x + 5041 - 6561 = 0}[/tex][tex](\frac{1}{2})\text{ (2x}^2\text{ + 142x - }1520)\text{ = 0}[/tex][tex]\text{ x}^2\text{ + 71x - 760 = 0}[/tex][tex]\text{ (x +}\frac{71+\sqrt[]{8081}}{2})(x\text{ + }\frac{71\text{ - }\sqrt[]{8081}}{2})=\text{ 0}[/tex]There are two possible height of the rectangle,
[tex]x_1\text{ = }\frac{-71-\sqrt[]{8081}}{2}\text{ = -80.45 in.}[/tex][tex]\text{ x}_2\text{ = }\frac{-71\text{ + }\sqrt[]{8081}}{2\text{ }}=9.45\text{ in.}[/tex]9.45 = 9.5 in. is the most probable height of the rectangle because a dimension must never be negative, thus, let's adopt 9.5 in. as the height.
The width must be = x + 71 = 9.5 + 71 = 80.5 in.
