The circumference C of a circle of radius r is given by:
[tex]C=2\pi r[/tex]a)
Substitute r=60 feet to find the circumference of the first track:
[tex]\begin{gathered} C_1=2\pi(60\text{feet)} \\ =120\pi\text{ feet} \\ =376.9911184\ldots\approx377\text{ feet} \end{gathered}[/tex]b) Use the same procedure as in problem a), but substitute r=85 feet.
c) Use the same procedure as in problem a), but substitute r=110 feet.
d)
Since the diameter of a circle is twice its radius, then the circumference C is given in terms of the diameter D by the following equation:
[tex]C=\pi D[/tex]Substitute D=150 ft to find the value of the circumference.
Problem 2
a) Using the equation that relates the circumference in terms of the radius:
[tex]C=2\pi r[/tex]Divide both sides by 2*pi to isolate r:
[tex]r=\frac{C}{2\pi}[/tex]Substitute C=150ft to find out the value of r:
[tex]r=\frac{150ft}{2\pi}=23.87324146\approx23.87[/tex]b) Use the same procedure as in part a) but substitute C=200ft.
c) This question asks for the diameter instead of the radius. Use the equation:
[tex]C=\pi D[/tex]Divide both sides by pi to isolate D:
[tex]D=\frac{C}{\pi}[/tex]And then substitute C=400 ft. You may also find the radius first and then multiply by 2 to find the diameter, since:
[tex]D=2r[/tex]