In the figure shown, lines k and m are parallel to each other. Is x = z

Target question: Is x = z ?
Before we examine the statements, let's first recognize that, since k||m, we can conclude that angles w and z are EQUAL


Okay, now onto the statements

Statement 1: x = w
We already learned that w = z
Statement 1 tells us that w = x
Since x and z are both equal to w, it must also be true that x = z
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: y = 180 - w
We can also REPHRASE this as y + w = 180
Since w = z, we can also replace w with z in the above equation to get: y + z = 180
In the diagram, we can see that since angles y and x are on the same line, then y + x = 180
Since both equations are set equal to 180, we can also write: y + z = y + x
From here, we can subtract y from both sides to get z = x
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

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