Theorem: A line parallel to one side of a triangle divides the other two proportionately.

Question

anonymous · Answer

In the figure below, segment DE is parallel to segment BC and segment EF is parallel to AB.
 

 
Which statement can be proved true using the given theorem?

 Segment BF = 16

 Segment BD = 20

 Segment BD = 15

 Segment BF = 32

jim766 · Answer

look at the two sides that touching DE
Since we that DE is parallel to BC we know that the 2 sides touching DE are proportional

jim766 · Answer

a proportion is when two fractions are equal to each other, so....
24/20 = 18/x

do you know how to solve a proportion?

anonymous · Answer

nope

jim766 · Answer

cross multiply
24/20 = 18/x
24x = 360

anonymous · Answer

now what?

jim766 · Answer

get the x by itself....
any ideas?

anonymous · Answer

15

jim766 · Answer

good...
now look at the picture....what the line segment under the 18 on the left side?