How do you find the area if diameter is 12 cm?
Consider that radius
I assume you meant "the area of a disk" because you say "diameter" (but it is not so clear from the question, you could have meant the area of a "sphere" (which is in 3D), but I am assuming you are talking about a "disk").
There is a simple formula for the area of a disk:
where r is the radius.
The diameter is twice the radius (by definition).
So in our case, since the diameter is 12cm,
the radius is 6cm.
Thus, the Area of a disk of diameter 12cm is:
That's it! Hope that helped.