Problem 5. A skating rink in the shape shown has an area of
2,800 ft”. Find a formula for the perimeter of the rink as a
function of the radius r.

Respuesta :

Answer:

[tex]P=\dfrac{\pi r^2+2800}{r} $ ft[/tex]

Step-by-step explanation:

Let the length of the rectangular part =l

The width will be equal to the diameter of the semicircles.

Area of the Skating Rink= [tex]2(\frac{\pi r^2}{2})+(lX2r)[/tex]

Therefore:

[tex]\pi r^2+2lr=2800\\2lr=2800-\pi r^2\\$Divide both sides by 2r\\l=\dfrac{2800-\pi r^2}{2r}[/tex]

Perimeter of the Shape =Perimeter of two Semicircles + 2l

[tex]=2\pi r+2\left(\dfrac{2800-\pi r^2}{2r}\right)\\=2\pi r+\dfrac{2800-\pi r^2}{r}\\=\dfrac{2\pi r^2+2800-\pi r^2}{r}\\=\dfrac{\pi r^2+2800}{r}[/tex]

The perimeter of the rink is given as:

[tex]P=\dfrac{\pi r^2+2800}{r} $ ft[/tex]

Ver imagen Newton9022
Ver imagen Newton9022