Final answer:
The constant of proportionality between y and x of 2 means the two variables are directly proportional, described by the equation y = 2x, resulting in a straight line graph passing through the origin (0, 0).
Step-by-step explanation:
When we speak of a constant of proportionality between two variables, such as y and x, we are discussing a situation where y is directly proportional to x. This means that as x increases, y increases by a consistent factor, and this relationship can be described with the equation y = kx, where k is the constant of proportionality. If the constant of proportionality between y and x is given as 2, the equation representing their relationship would then be y = 2x.
When graphed on a coordinate plane, a direct proportionality results in a straight line graph that passes through the origin (0, 0). This differs from an inversely proportional relationship, which would produce a curved graph that never intersects the axes. Understanding these concepts is essential for solving a variety of problems in mathematics and physics.