Final answer:
The constant of proportionality in the equation y=7x is 7, which is the coefficient of x in the equation, representing a direct proportional relationship between x and y.
Step-by-step explanation:
The equation given describes a proportional relationship between x and y, which is expressed as y = 7x. In such a relationship, when discussing direct proportionality, the constant of proportionality is the factor that relates the two variables. This can be represented as y = kx, where k is the constant of proportionality. In this case, the constant of proportionality is the coefficient of x in the equation, which is 7. Therefore, whenever x changes, y will change by seven times that amount. This means that if x is doubled, y will also double. The graph of this relationship would be a straight line passing through the origin, confirming the direct proportionality.