How do you work out the circumference and area of a circle?

When working with circles we use which is a number that stays the same no matter how big the circle. The number starts with 3.1415.... and goes on forever, this number is programmed into the calculator, so we don't need to remember it.The circumference of a circle is an easy thing to work out as long as you keep your formula in mind. All it is is another word for the perimeter of the circle.To work out the circumference we need to use c=2r or c=d (these are the same as this is because the diameter is equivalent to 2x the radius). Calculators have a button and so this can be an easy calculation. To remember this equation I use the rhyme "c 2 s r nice" (see two pies are nice).To work out the area of a circle we need a different equation, a=r². If you are given the diameter, you must convert it to a radius (d=2r) and then use the equation. I use the rhyme "(a)pple (pi)es a(r)e (2) nice)".