Reason 1. Given
Reason 2. Definition of Equilateral Triangle
Reason 3. Given
Reason 4. Given
Reason 5. SAS Triangle Congruence
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Anywhere you see "given", it's basically just restating what was given in the instructions. Recall that equilateral triangles have all three sides the same length, so that's how we're able to say PK = PL in step 2. The SAS refers to side angle side.