Question

Benito wrote the equations shown about the figure. Explain Benito’s errors.

Answer 1

Answer:

• Benito's error was using the equal sign (=) instead of the congruency symbol (≅).

Explanation:

Benito's error was using the equal sign (=) instead of the congruency symbol (≅).

The congruency symbol (≅) means that the elements (segments, angles or figures in general) have the same measure, i.e. they have equal lengths for the segments or equal measure for the angles.

For instance, it is an error saying that the segment AB is equal to the segment BC because, as you clearly see in the picture, they are not same; they have the same length but they are joining different points, that makes them different in essence, although they have the same length. They would be equal only if they are the same figure.

In mathematics, you must not say that two different segments or two different angles are equal but they are congruent, which means that their lengths are equal. The use of equal is reserved for numbers and variables, not for figures like segment, points, angles, polygons.