Question

What is the radius of a circle with the circumference 22m?

Answer 1

r = 3.5m

Explanation:

What formulas do you remember about circles?

`A = \pi r^(2)` probably? That doesn't help for this one though.

How about
`C = \pi d` ?

That's the one you need: circumference equals
`\pi` times the diameter. From that you can solve for diameter.

Oh but wait, the question asks for the radius. Do you remember a relationship between radius and diameter? Of course: radius is just half the diameter: r = d/2

So now we have everything we need to find the radius of this circle with circumference 22m.

`C = \pi d\\22m = \pi d\\d = 22m/\pi \\d = 22m/3.141\\d = 7.00m`

Now that we know the diameter, just half it to get the radius

r = d/2

r = 7.0m/2

r = 3.5m

I hope that helped. A lot of words, but I wanted to make sure you understood. Take care.