If the slope of a line is -2, what is the slope of a line perpendicular to it?

When two lines are perpendicular, it means that their slopes are negative reciprocals of each other. The negative reciprocal of -2 is $\frac{1}{2}$. Therefore, if the slope of a line is -2, the slope of a line perpendicular to it would be $\frac{1}{2}$. This concept is crucial in understanding the relationship between the slopes of perpendicular lines in geometry. Students are often tested on this fundamental concept and understanding it is essential for success in geometry.