30 POINTS

Fencing encloses a rectangular backyard that measures 200 feet by 800 feet. A blueprint of the backyard is drawn on the coordinate plane so that the rectangle has vertices (0,0) (0,40) (10,40) and (10,0).

A circular flower garden is dug to be exactly in the center of the backyard, with a radius of 60 feet.

What is the equation of the flower garden represented on the blueprint?

(x _ _)^2 + (y _ _)^2 = _​

Respuesta :

Answer:

The equation is [tex](x-5)^{2}+(y-20)^{2}=9[/tex]

Step-by-step explanation:

Given the following equation in the plane :

[tex](x-a)^{2}+(y-b)^{2}=R^{2}[/tex]

The set of points [tex](x,y)[/tex] that satisfy the equation graph a circle in the plane.The circle is centered at [tex](a,b)[/tex] and the radius of the circle is R.

For example, the set of points that satisfy : [tex](x-2)^{2}+(y-3)^{2}=9[/tex]

graph a circle of radius [tex]\sqrt{9}=3[/tex] centered at the point [tex](2,3)[/tex]

The first step to solve this exercise is to find the center of the circle.

The rectangle has vertices [tex](0,0),(0,40),(10,40)[/tex] and [tex](10,0)[/tex] so they will form a rectangle with width 10 units and height 40 units.

Given this situation, the center of the rectangle is at [tex](5,20)[/tex] (Half of the width in the first coordinate and half of the height in the second one)

The equation of the flower garden will be

[tex](x-5)^{2}+(y-20)^{2}=R^{2}[/tex]

The final step is to find the value of R.

Given that the rectangular backyard width is 200 feet and this is represented with a rectangle in the blueprint with width 10 units

[tex]10units=200feet[/tex] ⇒ [tex]60feet=\frac{(60).(10)}{200}units=3units[/tex]

The radius of 60 feet is represented with 3 units in the blueprint.

Now we replace [tex]R=3[/tex] in the equation :

[tex](x-5)^{2}+(y-20)^{2}=3^{2}[/tex] ⇒

[tex](x-5)^{2}+(y-20)^{2}=9[/tex]

And that is the equation of the circle.