Although Jessica’s construction satisfies the three conditions, similarly to the previous
solutions, it reveals distinct features in terms of manipulation. Such differences show that Jessica’s thinking process is also distinctive: the absence of measurements or calculations stands out, the construction of a slider allows changing the stick’s size; and moving the free point on the right side changes the size of the rectangle. This file reveals Jessica’s mathematical and technological fluency in that the GeoGebra construction is built under the perspective of geometrical properties and relations, rather than aiming at measuring or calculating. The quantitative relationship that she explains appears embedded in a geometric representation which is very powerful since it invites at manipulating and therefore generalizing. Adding a slider that controls the length of the stick involves analysing a variable that is not explicit in the statement of the problem; hence Jessica’s exploration goes far beyond what was
requested to solve the problem.