Help please ASAP I don’t understand

The area of a circle is represented by the equation:

We know that the diameter is two times the radius:

So if we know that the diameter of the circle is 24m, we can divide this by two in order to get the radius:

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So then we can plug this radius in to the equation for the area of a circle:

We are told to use 3.14 as pi, and not pi itself, so let's plug in 3.14 for pi:

Now we know that the area of this circle is 452.16 square meters.