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The area of 72 square yards is the difference of the area of the larger rectangle and the pool's area.
Let w be the uniform width of the deck.
Then the dimensions of the larger rectangle are (8+2w) yards and (10+2w) yards,
and its area is (8+2w)*(10+2w).
Thus you have this equation
(8+2w)*(10+2w) = 8*10 + 72.
Simplify it
80 + 20w + 16w + 4w^2 = 80 + 72
4w^2 + 36w - 72 = 0
w^2 + 9w - 18 = 0
= = .
Only positive root makes sense w = = 1.685 yards. ANSWER
CHECK. (8+2*1.685)*(10+2*1.685) - 8*10 = 72.0169 very close to 72 square yards. ! Correct !
Solved.
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Closely related lessons to it are the lessons
- Problems on the area and the dimensions of a rectangle surrounded by a strip
- Cynthia Besch wants to buy a rug for a room
- Problems on a circular pool and a walkway around it
in this site.
Also, you have this free of charge online textbook in ALGEBRA-I in this site
- ALGEBRA-I - YOUR ONLINE TEXTBOOK.
The referred lesson is the part of this online textbook under the topic
"Dimensions and the area of rectangles and circles and their elements".
Save the link to this online textbook together with its description
Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson
to your archive and use it when it is needed.