Question

The triangles are similar. If DE = 24, EF = 42, and AB = 8, find BC.

Answer 1

$\Delta ABC\sim\Delta DE F\\\\\frac{|EF|}{|DE|}=\frac{|BC|}{|AB|}\\\\substitute:\\\\\frac{|BC|}{8}=\frac{42}{24}\\\\\frac{|BC|}{8}=\frac{7}{4}\ \ \ \ /\cdot8\\\\|BC|=7\cdot2\\\\|BC|=14\\\\\\Answer:D.$