Barbara plotted an elevation below sea level on a number line and labeled it A. She plotted Point B above 0, a distance that is exactly as far from 0 as Point A is. Explain what you know about Point B.

Answer 1

Since Point A is an elevation below sea level, it is represented on the number line as a negative value. Let's denote the value of Point A as \(-x\) (where \(x\) is a positive number).

Point B is plotted at a distance that is exactly the same as Point A from 0, but since Point B is above 0, it will be a positive value. Thus, Point B would be represented as \(x\).

This means that Point B is the reflection of Point A across the origin on the number line. In other words, if Point A is at \(-x\) (below sea level), then Point B is at \(x\) (above sea level), and both points are equidistant from 0.

To summarize, Point B is a positive distance that is equal to the absolute value of Point A, and it is positioned on the number line above 0, while Point A is located below 0.