Question

radius =
diameter =
area =
circumference =
9)

Explanation:

Step1: Recall radius - diameter relationship

The diameter $d$ of a circle is twice the radius $r$, i.e., $d = 2r$. Given the radius $r = 18.5$ ft, the diameter $d=2\times18.5 = 37$ ft.

Step2: Calculate the area of the circle

The formula for the area of a circle is $A=\pi r^{2}$. Substituting $r = 18.5$ ft, we get $A=\pi\times(18.5)^{2}=\pi\times342.25\approx3.14\times342.25 = 1074.665$ square - feet.

Step3: Calculate the circumference of the circle

The formula for the circumference of a circle is $C = 2\pi r$ or $C=\pi d$. Using $r = 18.5$ ft, $C = 2\times\pi\times18.5=37\pi\approx37\times3.14 = 116.18$ ft.

For the second circle with $r = 3.6$ in:

Step4: Find the diameter

Using $d = 2r$, with $r = 3.6$ in, $d=2\times3.6 = 7.2$ in.

Step5: Calculate the area

Using $A=\pi r^{2}$, with $r = 3.6$ in, $A=\pi\times(3.6)^{2}=\pi\times12.96\approx3.14\times12.96 = 40.6944$ square - inches.

Step6: Calculate the circumference

Using $C = 2\pi r$, with $r = 3.6$ in, $C=2\times\pi\times3.6 = 7.2\pi\approx7.2\times3.14=22.608$ in.

Answer:

For the circle with $r = 18.5$ ft:
Radius = $18.5$ ft
Diameter = $37$ ft
Area $\approx1074.665$ square - feet
Circumference $\approx116.18$ ft

For the circle with $r = 3.6$ in:
Radius = $3.6$ in
Diameter = $7.2$ in
Area $\approx40.6944$ square - inches
Circumference $\approx22.608$ in