Circumference and Diameter

[Witness1970]

On 11/15/2025 at 5:21 AM, Witness1970 said:

X/2*(X-1)

 

20 hours ago, kejedo said:

20×19/2=190

total handshakes. This formula accounts for the fact that each of the 20 people shakes hands with 19 others, but dividing by two prevents double-counting each handshake (since A shaking B's hand is the same handshake as B shaking A's hand). 

You changed my formula correctly.  My formula would be X/2*(x-1) = 10*19.  20*19/2 gives the same result.

[kejedo]

In an odd little town, there was an odd little stream, with odd little fish in an odd little team. A stranger approached a local fisherman, And asked him how much his odd little fish weighed. The odd little man replied: All the fish in this stream weigh exactly 1/2 of a pound plus 1/2 of a fish. How many pounds does an odd little fish weigh?

[kejedo]

In an odd little town, there was an odd little stream, with odd little fish in an odd little team. A stranger approached a local fisherman, And asked him how much his odd little fish weighed. The odd little man replied: All the fish in this stream weigh exactly 1/2 of a pound plus 1/2 of a fish. How many pounds does an odd little fish weigh?

[kejedo]

You might have thought I started this thread, but I didn't. Brother Kyle did, and it is not even written in tagalog. Many here know I try to end phone conversations first, b/c I don't  want to be known  as a long talker, but the other reason a math teacher should  say Good bye first: If walking down the street with friends and the store says 20 percent off, the math head should already be multiplying by .8 and recognize first if it is a good buy. 

Edited November 16 by kejedo

[kejedo]

Lived in Maine and NH for twenty years and lots of horses around there. Here's an old yarn: A horseman goes into a tack store looking for a horse blanket. Store clerk goes in back and comes out with one for 20 bucks. Potential customer says, that's too much, do you have anything less expensive? Store clerk goes in back and since this is the only blanket in stock, he comes back out with same blanket and says,"This one is only fifteen." Customer says that's a deal but it gets cold around here, I'll take both for 25. Qapla may have a better horse saga.Giddyup from YS.

[kejedo]

Quick think warm up.- Take the head from an odd number and it becomes even; then take the tail and it is a real Bible mother. Ain't that odd? Not ain't : use isn't. Okay, isn't that quisn't.

[kejedo]

What number do you get when you multiply all of the numbers on a telephone's number pad?

[Mike047]

The answer would appear to be zero.

[kejedo]

I would sometimes put word or number problems on the board. One day I was entering a series of numerals, one digit at a time, for students to multiply, aloud. After awhile, the next entry was zero. One student started chuckling, b/c obviously any number or product multiplied by zero, is zero. Same with the telephone.

[kejedo]

In any math formula that concludes 2 equals 1, there is generally a hidden division by zero, which is undefined in our number system. In calculus, we are using formulae; in which  the denominator is approaching zero. Haven't done calculus probs in a long time, but my overloaded brain will not stop over analyzing, sorry.

 

[kejedo]

Nodes inspire math: https://99percentinvisible.org/article/the-seven-bridge-problem-how-an-urban-puzzle-inspired-a-new-field-of-mathematics/

 

[kejedo]

A ladder 10 feet long leans against a vertical wall. The base of the ladder is 6 feet away from the wall. How high up the wall does the ladder reach?

 

 

[Mike047]

13 hours ago, kejedo said:

A ladder 10 feet long leans against a vertical wall. The base of the ladder is 6 feet away from the wall. How high up the wall does the ladder reach?

The ladder reaches 8 feet up the wall.

[kejedo]

1 hour ago, Mike047 said:

The ladder reaches 8 feet up the wall.

Right:6,8,10 is a Pythagorean triplet (multiple).

 

[kejedo]

The 22nd and 24th presidents of the United States of America had the same parents but were not brothers. How can this be possible?

 

[careful]

we all have the same parents.

[kejedo]

I heard someone (on tv, of course) say, you can get the answer by guessing, which isn't scientific. If you use the foil method to solve polynomials, you undoubtedly used guess (and check.)

 

[kejedo]

Differences in measurement and numbering have led to questionable  conclusions:

• Napoleon was of average height for his time and place, but measurements (Fr?) have led people to later conclude he was of short stature.
• US and UK used to name large numbers differently. Thought to have been standardized in or around 1974.
• Not  directly due to measurements, but people believed that the Gr.  wall of China was visible from space: How far? Few feet into space, yup you can see it - from the moon? only with a telescope.  It's a about 13 feet wide and 21 feet high. 
  • Sizes of temples: see the definition of  cubits.(Bible appendix)

 

[kejedo]

5 minutes ago, kejedo said:

Differences in measurement and numbering have led to questionable  conclusions:

• Napoleon was of average height for his time and place, but measurements (Fr?) have led people to later conclude he was of short stature.
• US and UK used to name large numbers differently. Thought to have been standardized in or around 1974.
• A cord of wood has a somewhat standard measurement, US and Canada, and some definition of how tightly stacked (mouse can run thru, but not a cat).
• Not  directly due to measurements, but people believed that the Gr.  wall of China was visible from space: How far? Few feet into space, yup you can see it - from the moon? only with a telescope.  It's a about 13 feet wide and 21 feet high. 
  •  
  • Sizes of temples: see the definition of  cubits.(Bible appendix)