18) answer is A: Reflect across the line y = -3. This is the horizontal line that cuts the trapezoid in half, forming a mirror image so to speak.
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19)
Answer is choice A) 2
CB/GF = CD/GH
6/3 = 4/GH
6*GH = 3*4
6*GH = 12
GH = 12/6
GH = 2