Answer:
The correct option is B. Alternate Exterior angles theorem
Explanation:
Let name the marked angles in the figure as x and y
Given that : x = y
So, to state which theorem does the diagram illustrate, we first need to find the relation between the angles x and y
Alternate interior angles : The angles which lie interior to the parallel sides but on the opposite side of the transversal.
But x and y lie exterior to the parallel lines, So this option is rejected.
Alternate exterior angles : The angles which lie exterior to the parallel sides but on the opposite side of the transversal.
But x and y lie exterior to the parallel lines, So this option is correct.
Same side interior angles theorem : This theorem states that the sum of same side interior angles in 180.
So it can't be said angle x = angle y by using this theorem. So, this option is rejected
Corresponding angles theorem : The angle which lie at same relative position of the transversal.
But, angle x and angle y lie on the opposite side. So, this option is rejected
Hence, The correct option is B. Alternate Exterior angles theorem