You can put this solution on YOUR website! The formula for the area (A) of a circle is usually given as a function of the radius (r), and involves the irrational number pi ().
The formula is
Since the radius is half of the diameter (D), the formula using the diameter would be
With a diameter of 29 mm, The area of the circle, in square millimeters would be
If you are using a calculator that has pi as one of the keys, you can use a very close pi approximation, and get a more accurate result than just entering a pi approximation with a few decimal places, like 3.14, or 3.1416
If you use 22/7 as your approximation for , which rounds to 661.
