Refer the diagram at the right. identify each angle pair as adjacent, vertical, or neither 7-12

Adjacent angles are angles that are side by side (right next to each other).  They share a side.  #7 and 11 are pairs of adjacent angles.

Vertical angles are angles that are directly across from each other.  They are the same angle.  #8 and 9 are vertical angles.

#10 and 12 do not fit either of these descriptions so they are neither.

1. 20 the easiest method to find a common denominator is to times the two denominators together