How did the geographic setting of north america- including its relation to asia, europe, and africa- affect its subsequent history?

The American continent is geographically inaccessible and secluded, separated by two oceans from any other countries.  

This made colonization (or invading a country) of North America which possibly only through a sea. That removed and eradicated nations with large armies as threats. The only power that could influence North America was a nation with a powerful and tough navy, like England’s.  

To our north countries like, Canada was resolved by the French, who were our alliances. To the south was Mexico, South America, and Central America.

Thus, at the start, North America had a geographic superiority against any conquering force: distance across an ocean. However, the United States of America can grow and establish their own identities separately from their parent and other countries.

answer: this problem has only trivial solutions, with all points on the same line. x=5 or x=7/5.

step-by-step explanation:

there are three triangles, and three unknowns: x, y=length of middle segment, and z=cos(angles marked with red arc).

we need

and law of cosines,

the three equations are

see attached image for solution.