Quote Originally Posted by Steve Litzell View Post
Are you saying my formula is not correct???Bore X 2 is same as bore X bore. Both forulas are good. Roy's method is what I was taught many years ago when I had hair and was very young. My formula is also correct for both metric and American, and if you try it you will see that it is spot on. It is just more modern way that's all. Steve
Bore x 2 does not equal Bore x Bore

Ex Bore = 4 inches = diameter of cylindere

4 inches x 2 = 8 inches
4 inches x 4 inches = 16 square inches

Area of circle = pi x R x R or in terms of diameter = D x D x pi/4
R = radius
D = diameter
pi = 3.14 .........
pi/4 = 0,7854 .....