...to determine the displacement of an engine.
I had come across this in an Algebra text book back in High School, wrote it down for future reference and appropriately secured it away. My 'Half-Zeimer's' (half-way 'there') eventually interfered, and I thought it was lost long ago. Now, in this age of turbochargers and nitrous, perhaps it is rendered as useless information. Unfortunately, I still find it interesting, as well as simpler than the explanation found on 'Google'! (This equation works!) Hope it helps with someone's curiosity.
Use appropriate decimals for fractions, and remember any 'overbore' or 'stroke' additions.

"Bore"(squared) X .7854 X "Length of Stroke" X "Number of Pistons" = "Displacement"

Take Care; Behave; "Don't Shoot!" (and)
"Happy T-ing!"

The "displacement" is calculated as "cubic inches"...

Take Care; Behave; "Don't Shoot!" (and)
"Happy T-ing!"

Should be "3.14 x Radius(squared) x length of stoke x number of pistons"

Those formulas are the same.

Using Marv's version for a 4" cylinder with 4" stroke I get 50.2656.

With Tom's version I get 50.2656. Pretty close.

For you guys in the rest of the world --
50.2656 cubic inches is 0.8237056 liters

or 73.7056 ml more than there is a standard wine bottle.

So, Fred, how many chips in a New Hampshire chocolate chip cookie?

-David-
It all depends..... Having grown up on a farm, it all depends on who (or what) is depositing the 'chips'!
Glad to see some are having some fun with this.

Take Care; Behave; "Don't Shoot!" (and)
"Happy T-ing"

The actual formula uses the radius rather than diameter and Pi. The 0.7854 is actually Pi/4. So the two formula are the same.
Personally I prefer using Pi as its much simpler to remember, indeed most calculator have it on the keypad.

I'm constantly calculating circular area in my work. I MUCH prefer (pi*D^2)/4 to 2*pi*R. Circles are almost ALWAYS given by diameter rather than radius. Who wants to have to convert a diameter to radius before doing the rest of the calculation? I'm so used to using the diameter formula, I have to think about what the radius formula even is anymore.

Besides, everyone knows pies ain't square . . . they're round !

-Rich-
"T-related?" Depends again on the 'pan' you have!....

Take Care; Behave; "Don't Shoot!" (and)
"Happy T-ing"

Marv, must be T related, my pan has a "teacup" !! ; )

David,

I am conducting a study on the number of chocolate chips in a NH chocolate chip cookie.
I will get back to you in a few weeks after I have eaten the required statistical sample.

AFred, are you sure it will only take a few weeks?

How do you find the sample size in statistics?

Step 1: Using the data given in the question, figure out the following variables:
za/2: Divide the confidence interval by two, and look that area up in the z-table: .95 / 2 = 0.475. ...
E (margin of error): Divide the given width by 2. 6% / 2. ...
: use the given percentage. 41% = 0.41. ...
: subtract from 1. 1 – 0.41 = 0.59.

Rich

cornbread are square!

You guys make my head hurt.................

David: You have calculated the P value, but you asked for the sample size, n. Recalling the Confidence Interval of the mean of n independent observations (ie., some number,n of choc chip cookies evaluated independently), is equal to the S Dev divided by the square root of n. You have Zalpha and the prob calculated correctly, you need to use the calculated p-value to find the interval width and set that Zalpha range equal to SDev/(sqrt n)and solve for n. I know you know this but the casual reader of your post may be confused, hopefully this clears it up. Best wishes for the Holidaze, jb

At one point a few years ago I ran out the speed of my TT based on engine RPM, gear ratios and tire circumference. Another time I calculated the weight of my TT based on tire pressure and tire/pavement contact area.

My big mistake was explaining these calculations to my wife. About half way through the explanation she walked away.

Cornbread doesn't taste square.

I expected a lot of pie.
I was not disappointed.