From the figure
A. alternate interior angles: 1
B. same side exterior: 4
C. vertical: 4 and 3
D. same side interior: 3
E. obtuse angle: 1
F. adjacent angle pairs: 1 and 2
G. alternate exterior: 2
H. corresponding: 4
I. complimentary:
Parallel lines are lines that will never meet. Some angle theorems apply when a pair of parallel lines intersect with a transversal line, as shown in the image.
Some of the are utilized in the problem and definition of some of them
Adjacent angles are those that are next to each other and are separated by a line from the other angle. Angles 1 and 2 in the diagram alternate.
Obtuse angles are those that are greater than 90 degrees but less than 90 degrees.
Vertical angles are the angles formed when two lines intersect.