How many digits of pi did you memorize?

[edro]

3.14159

5 digits after the decimal place.

I have heard that humans are good at remembering and counting up to 5 items quickly and easily because we have 5 fingers on each hand.
For instance, if there are 5 objects or less spaced randomly on the table and you glance at it for a split second, you can recognize 5 instantly.
If there 6 or more, it takes more time to determine the number.

 

[OverVolt]

wat

I leave my logic fails up for everyone to behold the fail.

 

[SKORPI0]

Remember, it was a couple thousand years before more than the first ten digits were known.

Interesting read....
Approximations_of_π :awe:

 

[DrPizza]

Also I hate when people tell me to use 22/7 cuz its WAY off from that. You'd do better to just use 3.14 if you arent gonna .

I interviewed a math teacher candidate who said something about just using 3.14 "instead of the exact value which is 22/7."
Next!

 

[OverVolt]

I interviewed a math teacher candidate who said something about just using 3.14 "instead of the exact value which is 22/7."
Next!

I'd hire them!

 

[mnewsham]

I interviewed a math teacher candidate who said something about just using 3.14 "instead of the exact value which is 22/7."
Next!

Just remember 4√(2143/22)

 

[Rubycon]

This is proof that Sicilian pizza is the best. :awe:

As for a demonstration for the area formula (this'll be hard without a picture to show.)

Picture a pizza cut into 8 pieces. (of course I would use pizza to "prove" the area formula)
Line up 4 slices side by side pointing forward. Line up the other 4 slices in front of these pointing toward you. Mesh them together, you get something roughly in a rectangular (or, closer to the shape of a parallelogram), except the side closest to you and farthest from you would be curvy from the arcs of crust.

Repeat this, except cut the pizza into 16 slices. Now, it's closer to the shape of a parallelogram, though the angles in the corners are closer to 90 degrees. Now, imagine doing this with a pizza cut into 100 slices... 1,000,000 slices... It gets closer and closer to the shape of a rectangle. The height is obviously getting closer to the radius of the circle, and the length is getting closer and closer to a straight line with a length of half the circumference. Area = length times width = 1/2 * 2 pi r * r.
Though, this really doesn't constitute "proof."

 

[Farmer]

As for a demonstration for the area formula (this'll be hard without a picture to show.)

Picture a pizza cut into 8 pieces. (of course I would use pizza to "prove" the area formula)
Line up 4 slices side by side pointing forward. Line up the other 4 slices in front of these pointing toward you. Mesh them together, you get something roughly in a rectangular (or, closer to the shape of a parallelogram), except the side closest to you and farthest from you would be curvy from the arcs of crust.

Repeat this, except cut the pizza into 16 slices. Now, it's closer to the shape of a parallelogram, though the angles in the corners are closer to 90 degrees. Now, imagine doing this with a pizza cut into 100 slices... 1,000,000 slices... It gets closer and closer to the shape of a rectangle. The height is obviously getting closer to the radius of the circle, and the length is getting closer and closer to a straight line with a length of half the circumference. Area = length times width = 1/2 * 2 pi r * r.
Though, this really doesn't constitute "proof."

This is the same as a calculus based proof, whereby you take infinitesimal path segments ds about the circumference. In this limit it is equivalent to the familiar r dtheta, where dtheta is now an infinitesimal angle element. This is what I had mentioned before. What you are saying boils down to this: an n-sided normal polygon becomes a circle in the limit n goes to infinity. Calculus advances upon earlier attempts using inscribed polygons because it introduces "the limit as n goes to infinity." The concept of a "limit" was not well defined until Newton, or arguably, until analysis.

I'm saying there must be geometric proofs other than calculus based proofs. For instance, there is are several classical proofs of the Pythagoras theorem, all of which are completely geometrical.

Having attended grade school in 'merica, we were not even introduced in the slightest to this concept.

 

[Dr. Zaus]

unit circle proof was good enough for me.

Dr. Pizza doesn't know how to math. I checked into it.

Oh, and the earth is mostly round.

not spherical, but it is mostly round.

a bit bumpy, but it is mostly round: measured at the equator from one ocean to another.

 

[Joseph F]

Dr. Pizza doesn't know how to math. I checked into it.