How do adults perceive, analyse and measure slope?

Slope is a mathematical concept that is both fundamental to the study of advanced calculusand commonly perceived in everyday life. The measurement of steepness of terrain as a ratio is an example of an everyday application the concept of slope. In this study, a group of pre-service teachers were tested for their capacity to mathematize the measurement of steepness. Findings suggest that accuracy in the measurement of steepness may be related to success in linear algebra as they are both related to the perception of slope as a ratio.