Beware of Congurence in Common Core (defend against the "dumb you down" army)

[kirby urner]

Understand congruence in terms of rigid motions

   G-CO.6. Use geometric descriptions of rigid motions to transform figures and to predict the effect of a given rigid motion on a given figure; given two figures, use the definition of congruence in terms of rigid motions to decide if they are congruent.
   G-CO.7. Use the definition of congruence in terms of rigid motions to show that two triangles are congruent if and only if corresponding pairs of sides and corresponding pairs of angles are congruent.
   G-CO.8. Explain how the criteria for triangle congruence (ASA, SAS, and SSS) follow from the definition of congruence in terms of rigid motions.


COMMON CORE STANDARDS

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What we in the IVM community have discovered is the importance of enantiomorphism and chirality. 

The thalidomide story is just the tip of the iceberg (left or right handed iceberg).

Those ethnicities flocking to Common Core standards, among them many Anglo, retro-Anglo, Euro, other troglodytes and antediluvians (old world bottom feeders), are harping on Congruence as usual.

Those who've played Tetris know that a Left L cannot a Right L make given the rigid motions permitted.

Inside-outing, turning a left-handed glove into a right-handed glove, is not a matter of simple rotation either.

So is a Left Handed glove congruent to a Right Handed glove, i.e. is a figure congruent to its mirror image?

Statistical studies will show that most Commoners will say "yes", especially the teachers.

Are they sufficiently aware of Chirality then?  Spirals?  Handedness?

Something Koski and I have discussed quite a bit.

My advice:  don't flock.  Stand back from the onrush.  Don't hop on the bandwagon.  If you see a lot of herd-minded Anglos stampeding in a given direction, you KNOW it's likely a bad idea (Anglos ain't the smartest in the room). 

"Never trust an Englishman" etc. (their law is all based on double standards).

Kirby

[John Brawley]

Things either are congruent or they're not, but things that are not at the
moment congruent, may become so IFF they have at least one common state of
being.
(Left handed glove becomes righthanded; it _can_ become righthanded.)

Things which cannot ever become congruent, by any combination of inversions,
eversions, rotations, expansions, contractions and so forth, are always and
only incongruent.

(*g*)

--JBw

[kirby]

> Are they sufficiently aware of Chirality then?  Spirals?  Handedness?
>

Joe Niederberger

Posts: 1,087
Registered: 10/12/08
Re: Must equality "=" be defined as the identity relation or as "the
same"?
Posted: Apr 30, 2012 4:34 PM


Your point is well taken -- and it shows also that in certain contexts
even congruence does not guarantee that "all" properties are the same.
Equality is tough. Is Kirby now equal to the Kirby of yesterday?

Joe N

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