Why is it useful for historians to base certain studies on the analysis of historical themes? a. there are fewer historical themes than there are regions or periods. b. the same themes apply to people living in very different times and places. c. all the cultures in a particular region respond to historical themes in the same way. d. experience has confirmed that analyzing themes is the most effective approach to history

The same themes apply to people living in very different times and places. (I think)

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.

i believe the answer is c