Answer: C) 9 feet
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Work Shown:
Let's call the "height" to be the "width".
The area of a rectangle is
area = length*width
We're told the width is 8.5 feet
If the length is some unknown variable L, then
area = length*width
area = L*8.5
area = 8.5L
We want the area to be at least 76.5 square feet
This means 8.5L is either equal to 76.5, or larger than it
[tex]\text{ area } \ge 76.5\\\\\\8.5L \ge 76.5\\\\\\\frac{8.5L}{8.5} \ge \frac{76.5}{8.5} \ \ \text{ ... divide both sides by 8.5}\\\\\\L \ge 9\\\\\\[/tex]
This shows the length can be 9 feet or larger.
In other words, the minimum length is 9 feet.
