2000 AMC 12 Problem 10

Below is the professionally curated solution for Problem 10 of the 2000 AMC 12, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2000 AMC 12 solutions, or check the answer key.

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Concepts:transformation3D geometrycoordinate geometry

Difficulty rating: 1390

10.

The point P=(1,2,3)P = (1, 2, 3) is reflected in the xyxy-plane, then its image QQ is rotated by 180180^\circ about the xx-axis to produce R,R, and finally, RR is translated by 55 units in the positive yy direction to produce S.S. What are the coordinates of S?S?

(1,7,3)(1, 7, -3)

(1,7,3)(-1, 7, -3)

(1,2,8)(-1, -2, 8)

(1,3,3)(-1, 3, 3)

(1,3,3)(1, 3, 3)

Solution:

Reflecting (1,2,3)(1, 2, 3) in the xyxy-plane gives Q=(1,2,3).Q = (1, 2, -3).

Rotating 180180^\circ about the xx-axis negates yy and z,z, giving R=(1,2,3).R = (1, -2, 3).

Translating 55 units in the positive yy direction gives S=(1,3,3).S = (1, 3, 3).

Thus, the correct answer is E.

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