Anonymous
Anonymous asked in Science & MathematicsPhysics · 1 month ago

Which one is correct??

My teacher said it's a reflection, but my entire class was arguing that she's wrong and it's actually a rotation. My teacher refused to explain the reasoning behind her statement (that it's a reflection) 

Is she's wrong or right? If she's not mistaken please explain WHY!!!!!

Update:

@? Your explanation is a bit misleading, but I figured out the correct answer based on your answer......so I rewarded you with favorite answer.

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5 Answers

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  • neb
    Lv 7
    1 month ago
    Favourite answer

    It’s based on the definition of congruence. Congruence means the rectangles match when superimposed. They are not congruent without a rotation. If you take the ‘reflected’ rectangle and superimpose it on the non-reflected rectangle without doing a rotation they will NOT be congruent (e.g line AB is not the same line as MN)

    Update: upon looking at the picture again, it’s not clear that you can do a rotation without also doing a translation. To rotate the bottom figure, you would rotate it about its center of axis - but that would not align it with the upper figure. You would also require a translation to superimpose them.

  • Whome
    Lv 7
    1 month ago

    If the entire class is arguing that it is a rotation and not a reflection, the whole class is silly. It is clearly a reflection across the x axis.

    However, it is also a fairly easy rotation if one chooses an axis of rotation centered on the x axis and four vertical lines to the left of the y axis. Such rotation axis would be perpendicular out of the paper. Philomel calls it (-2,0), which could be correct if each grid line is ½ unit from the next. I see no clear indication of line spacings information.

  • ?
    Lv 7
    1 month ago

    If you reflect KLMN over the x-axis, you get ADBC.

    I don't agree with Philomel that you get the two figures to match by rotating around (-2,0).  There may be a rotation that will make the two figures match, but it's not at all obvious where the center of that rotation would be.  So I'll go with your teacher and say it's a reflection.

  • 1 month ago

    It can be either a reflection or a rotation.

    Reflect over x axis.

    Rotate  about (-2,0).

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  • 1 month ago

    its reflected over the x-axis

    but its also a rotation 180 degrees

    both are correct

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