Question

Which of the following is the rule for rotating the point with coordinates (x,y), 180° clockwise about the origin? A. (x,y)→(y,−x) B. (x,y)→(−y,−x) C. (x,y)→(y,x) D. (x,y)→(−x,−y)

Answer 1

Hey there! I'm happy to help!

If you reflect a point across the x-axis, you have (x,y)⇒(x,-y). If you reflect across the y-axis, you have (x,y)⇒(-x,y). A 180° rotation is the same thing as reflecting across both the x and y axes. This means that the rule for rotating the point with coordinates (x,y) 180° clockwise about the origin is D. (x,y)⇒ (-x,-y).

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