In similer triangles, you want to find how much it is reduced or enlarged by, in this case you know that 20/5 is 4 and 12/3 is 4 so you know that x/<u><em>4</em></u><u><em> </em></u> must be <em>4</em>. So you solve this by doing <u><em>4</em></u> × <em>4</em> which equals 16.
