Solution:
The circumference C, of a circle is;
[tex]C=\pi r^2[/tex]
Given;
[tex]C=40cm,\pi=3.14[/tex]
The radius r, is;
[tex]\begin{gathered} 40=3.14(r^2) \\ \text{Divide both sides by 3.14} \\ \frac{40}{3.14}=\frac{3.14(r^2)}{3.14} \\ r^2=12.74 \\ \text{Take the square root of both sides;} \\ \sqrt[]{r^2}=\sqrt[]{12.74} \\ r=3.57 \end{gathered}[/tex]
The radius of the circle is 3.57cm
