Width = 4.5 yards
Length : 12 yards
Explanation
the area of a rectangle is given by:
[tex]\text{Area}=\text{length}\cdot\text{ width}[/tex]
so
Step 1
a)
Let l represents the length
let w represents the width
so
I)the area of the rectangle is 54
replace
[tex]\begin{gathered} \text{Area}=\text{length}\cdot\text{ width} \\ 54=l\cdot w\rightarrow equation(1) \end{gathered}[/tex]
ii)the length of the triangle is 3 yd more than twice the width ( in other words you have to add 3 to twice the width to obtain the length)
so
[tex]l=2w+3\rightarrow\text{equation}(2)[/tex]
Step 2
Solve the equations
[tex]\begin{gathered} 54=l\cdot w\rightarrow equation(1) \\ l=2w+3\rightarrow\text{equation}(2) \end{gathered}[/tex]
a) replace the l value form equation (2) in equaiton(1)
[tex]\begin{gathered} 54=l\cdot w\rightarrow equation(1) \\ 54=(2w+3)\cdot w \\ 54=2w^2+3w \\ \text{subtract 54 in both sides} \\ 54-54=2w^2+3w-54 \\ 0=2w^2+3w-54 \end{gathered}[/tex]
now, we have a quadratic equation, we can use the quadratic formula
[tex]\begin{gathered} 0=2w^2+3w-54\rightarrow0=ax^2+bx+c \\ so \\ a=2 \\ b=3 \\ c=-54 \\ x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a} \\ \text{replace} \\ w=\frac{-3\pm\sqrt[]{3^2^{}-4(2)(-54)}}{2(2)} \\ w=\frac{-3\pm\sqrt[]{9+432}}{4} \\ w=\frac{-3\pm\sqrt[]{441}}{4} \\ w_1=\frac{-3+21}{4}=\frac{18}{4}=\frac{9}{2}=4.5 \\ w_1=\frac{-3-21}{4}=\frac{-24}{4}=-12=-12 \\ the\text{ valid option is the positive, so} \\ w=4.5 \end{gathered}[/tex]
Width = 4.5 yards
b) now, replace in equation(2)
[tex]\begin{gathered} l=2w+3\rightarrow\text{equation}(2) \\ l=2(4.5)+3 \\ l=9+3 \\ l=12 \end{gathered}[/tex]
therefore, the answer is
length : 12 yards
I hope this helps you