Well "component speakers" is a *type* of speaker whereas 6x9 and 7x10 are
*sizes* of speakers so they really have nothing to do with another.

A component speaker is simply a speaker where the tweeter is mounted spearately
from the midrange/woofer instead of being mounted inside of it as a coaxial or
triaxial setup.  There would be a separate crossover (usually) to send the
appropriate frequencies to each of the "components".

"Generally" speaking component speakers are more of a high end category setup,
but you can have very good and very expensive coaxials and you can have
component speakers that are pieces of crap.

Component speakers, all else being equal, give you the ability to place the
tweeters aimed more directly at your ears.  (Sound from the tweeters does
not travel as well as bass sounds, and it's also more directional, so it's
more important that the tweeters not be hidden like the woofers.)  But, all
else is not always equal - often, component speakers will be higher quality,
just because they had to put more effort into making them to begin with, and
the target audience cares more about better sound.