Final answer:
The constant of proportionality of total weight to number of eggs is 45 grams per egg.
Step-by-step explanation:
To find the constant of proportionality, we need to divide the total weight by the number of eggs. In this case, the weight of 4 eggs is 180 grams. So, the constant of proportionality is:
180 grams / 4 eggs
Simplifying this, we get:
45 grams per egg