The lines that must be parallel for ∠9 to be congruent to ∠13 is c║ d converse of the corresponding angle theorem.
How to find the angles when a transversal cut parallel lines?
When a transversal line cut across parallel lines, angle relationships are formed. Examples are corresponding angles, alternate angles etc.
Therefore, the lines that must be parallel for ∠9 to be congruent to ∠13 is as follows;
∠9 ≅ ∠ 13
Therefore,
∠9 and ∠ 13 are corresponding angles. when c║ d converse of the corresponding angle theorem.
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