Are ∠2 and ∠7 vertical angles? a: no; the angles are not adjacent. b: yes; the angles form a linear pair. c: yes; the sides of the angles form two pairs of opposite rays. d: no; only one pair of opposite rays is formed by the sides of these two angles.

D because it order to have vertical angles you need to have two intersecting lines to create vertical angles. Also, it has to be "full" lines, not just reaching the vertical stem [in this example] but going through it. Angle 7 is vertical because both of its lines making it up intersect and are "full". However, angle 2 has only 1 "full" line while the other line ends when it touches the "stem".

it is contrapositive

i could not see the question too well so check yourself again too . this is because i want you to get it correct.

i think it would be 42cm