What is the constant of proportionality in the equation y=25X?

Which equation represents a proportional relationship that has a constant of proportionality equal to 1/5

Ab based on the given diagram, if m_1 = 60° then m 2 = 30 60 90 180

Suppose that a households monthly water bill (in dollars) is a linear function of the amount of water the household uses (in hundreds of cubic feet, hcf). when graphed, the function gives a line with slope of 1.65. if the monthly cost for 13 hcf is $46.10 what is the monthly cost for 19 hcf?