Question 620363
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 ({{{pi}}}).
The formula is
{{{A=pi*r^2}}}
Since the radius is half of the diameter (D), the formula using the diameter would be
{{{A=pi*(D^2/4)}}}
With a diameter of 29 mm, The area of the circle, in square millimeters would be
{{{A=pi*(29^2/4)=pi*(841/4)=pi*210.25}}}
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 {{{pi}}} ,
{{{A=(22/7)*(841/4)=(11/7)*(841/2)=9251/14=4625.5/7}}} which rounds to 661.