Question

do you understand?

1. essential question how can you tell whether a figure is symmetric?
2. error analysis for the figure below, adam was asked to draw all lines of reflection. his work is shown. what error did adam make? © mp.3

Explanation:

A line of reflection is a line that divides a figure into two congruent parts such that one part is the mirror image of the other. For the given light - bulb - shaped figure, we check the horizontal line of reflection. If we reflect the figure over the horizontal line, the top part (with the filament - like structure) and the bottom part (the screw - in base) are not congruent. A line of reflection must create two mirror - image halves. Since the horizontal line does not do this (the top and bottom have different shapes and details), Adam's error was including the horizontal line as a line of reflection.

Answer:

Adam included the horizontal line as a line of reflection. The figure is not symmetric about the horizontal line because the top (filament - like part) and the bottom (screw - in base) are not mirror images of each other. The vertical line may be a line of reflection (assuming the left and right sides are mirror images), but the horizontal line is incorrect.