Question

Which graph shows a method for finding the image of point D if the parallelogram is reflected across the dashed line?

On a coordinate plane, parallelogram A B C D has points (1, 2), (3, 4), (8, 4), (6, 2). A dashed line goes through points A and C.
On a coordinate plane, parallelogram A B C D has points (1, 2), (3, 4), (8, 4), (6, 2). A dashed line goes through points A and C. A red dashed line is drawn from point B to point D. D prime = B.
On a coordinate plane, parallelogram A B C D has points (1, 2), (3, 4), (8, 4), (6, 2). A dashed line goes through points A and C. A red dashed line splits the image into 2 equals parts with length of 1.4 centimeters.
On a coordinate plane, parallelogram A B C D has points (1, 2), (3, 4), (8, 4), (6, 2). A dashed line goes through points A and C. Point D prime is at (2, 6).
On a coordinate plane, parallelogram A B C D has points (1, 2), (3, 4), (8, 4), (6, 2). A dashed line goes through points A and C. A vertical dashed line is drawn through the image.

Answer 1

Choose the graph that shows dropping a perpendicular from D to line AC and marking off an equal distance on the other side (the one with the red dashed segment split into two equal parts).

Reason: reflecting across line AC means the line is the perpendicular bisector of the segment joining a point and its image, so you must drop a perpendicular from D to AC, find the foot, and go the same distance past the line to get D'. (D' is not B; the actual reflected point is about (5.245, 4.642).)