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Al Bundy

(lp13-30) wrote in news:28766-44E007C7-206@storefull-
3153.bay.webtv.net:

Al, you said you guarantee your math, but you are wrong. A 5" and 6"
SQUARE are 25 and 36 square inches respectively, so your numbers are way
off. The numbers you came up with are for 10" and 12". The RADIUS of the
5" will be 2.5", and the 6 =3". We actually had a guy a work that said
two 9" ducts would equal one 18". That was about 5 years ago and we
still laugh about it. BTW, an easy way to figure area of a circle is
that it is about 21% less than that of a square the same size as the
diameter of the circle, whether it is 1 inch or 1 mile. Larry

The RADIUS of the 5" will be 2.5", and the 6 =3".

Duhhh!! Boy did I blow that part mixing up radius with diameter...well
almost. Gotta stop posting so late. Yes you are right.

The percentage difference is still correct all being a function of pi which
is what I was trying to get across. == Note, Al is saving face here :-)

The difference in area between a 5" circle and a 6" circle is 44% more!

And the difference between a 10" and 12" is also 44% !!!

Area of a circle is Pi(radius)(radius)
Pi=3.14159

3.14 x2.5 x 2.5 = 19.6 sq in.
3.14 x 3 x 3 = 28.3 sq in

(28.3-19.6)/19.6 *100 =44%

BTW, an easy way to figure area of a circle is
that it is about 21% less than that of a square the same size as the
diameter of the circle, whether it is 1 inch or 1 mile

Thanks. Good tip for roughing it.

And the percentage difference of area between two circles is regardless of
whether it's diameter or radius as long as they are not mixed.