Answer
• 13. vertical angles.
,
• 14. corresponding angles
Explanation
Assuming r and s are parallel lines, and that the line u (marked with stars) is a transversal cutting r and s, then the angles formed (a, b, and c) acquire some special properties.
• 13
Regarding ∠a and ∠b are vertical angles, which means they have the same measure.
• 14
Regarding ∠a and ∠c they are corresponding angles, which means they have the same measure.
