angle <1 ≅ <2 because vertical angles are congruent, CD ≅ BD because a midpoint divides a line segment into two congruent segments.
Explanation:
1. Mark the angles formed by the bisecting lines with a "(" and ")" and label both with the numbers 1 and two for each angle to show that there are two angles and that they are congruent to eachother.
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1. put vertical lines through the middle of CD and DB to indicate they are both congruent.