Math
posted by James .
If ∆ ABC ~ ∆ DEF, BC = 12 cm, EF = 10 cm, and AC = 18 cm, find DF.

The triangles are similar (but not congruent).
That means that corresponding sides are all in the same ratio.
BC/EF = 12/10 = AC/DF = 18/DF
DF = 18*(5/6) = 15 
by ratios
DF/10 = 18/12
solve for DF 
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