I need help ASAP pls

m< B = 120°

Explanation:

The sum of the angles of a trapezoids 360°

m<c=m<D= 60°

60°+60°+2x=360°

120°+2x=360°

2x=360°–120°

2x=240°

x=240/2

x=120°

So : m<B =120°

answer at the divergent plate boundary in the middle of the ocean;