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A physical education teacher is planning to outline two adjacent identical rectangular areas for a new game that students will be learning. If the boundaries, including the center line, of this "court" must be marked with a single 50-yard roll of tape, what is the maximum area of one of the smaller rectangular spaces, rounded to the nearest tenth of a square yard?

Respuesta :

Answer:

52.1 yard²

Explanation:

Let us assume the length of the center line is a yards and the other side is b yards. Since it is two adjacent identical rectangle, from the diagram attached, the perimeter of the rectangle is:

3a + 4b = 50 yards

Making a the subject of the formula:

[tex]3a+4b=50\\a=\frac{50-4b}{3}[/tex]

The area of one rectangle is a× b, therefore for the two rectangles, the area is given as:

[tex]A=2(a*b)\\Substituting:\\A=2(\frac{50-4b}{3} )(b)\\A=\frac{100b-8b^2}{3}[/tex]

At maximum area, dA/db = 0

[tex]A=\frac{100b-8b^2}{3}\\\\\frac{dA}{db}= \frac{100}{3}-\frac{16b}{3} \\at\ maximum\ area\ dA/db=0\\0=\frac{100}{3}-\frac{16b}{3} \\\frac{100}{3}=\frac{16}{3}b\\16b=100\\b= 100/16=6.25\ yard \\[/tex]

Substituting b to find a

[tex]a=\frac{50-4b}{3}\\a=\frac{50-4(6.25)}{3}=25/3=8.33[/tex]

The maximum area of one of the rectangle = ab = 8.33 × 6.25 = 52.1 yard²

The maximum area of the two adjacent identical rectangle = 2ab = 104.2 yard²

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