Question

a) The value of $\pi$ is approximately 3.14. Explain why it isn't exactly 3.14.

b) Show how to find the circumference of a circle if the radius is 4 feet. Use 3.14 for $\pi$. Show your work

Answer 1

Well, there is nothing much to explain about why it isn't exactly 3.14... $\pi$ is the ratio between the circumference and the diameter of a circle. If you perform this division, the result will not be exactly 3.14, never. It's just a fact.

As for part (b), the we just stated that

$\pi=\dfrac{C}{2r}$

So, if we want to solve for $C$, we have

$C=2\pi r$

If you want to use 3.14 for $\pi$ and the radius is 4, the circumference will be

$C=2\cdot 3.14\cdot 4=25.12$