Answers and Explanations

PLANE GEOMETRY FOLLOW-UP TEST

1 . E

Mark    up  the figure:

The brackets    around  the 7   and 5   are meant   to  show    that    they’re

proportions,    not actual  lengths.    Since   the ratio   of  AB  to  BC  is  7   to  5,  you

can say that    7   parts   out of  12  are in  AB  and 5   parts   out of  12  are in  BC.

Because the whole   length  of   is 1,   and    

The midpoint    of   divides    it  in  half,   so  each    half    length  is  half    of  

which   is   The    length  you’re  looking for is