The first figure has 3 line segments.
the second figure has 3+3 =32 = 6 line segments
the third figure has 3+3+3 = 33 = 9 line segments
the fourth figure has 3+3+3+3=34=12 line segments...
so it is clear that:
the 20th figure has 320=60 line segments.
Answer: 60
