Consider the figure below.
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Explanation:
First solve for angle c
This angle adds to the 58 degree angle to get 180
c+58 = 180
c = 180-58
c = 122
This is congruent to angle f as well because alternate interior angles are congruent when we have parallel lines like this.
You could also solve 58+b = 180 to follow the same basic path as above. Corresponding angles are congruent when we have parallel lines.