Unit 2 Introducing Proportional Relationships

A proportional relationship is a relationship between two quantities where the ratio of one quantity to the other quantity is constant.

A graph represents a proportional relationship if it is a straight line that passes through the origin (0,0).

The equation of a proportional relationship can be expressed as $$y = kx$$ , where $$k$$ is the constant of proportionality.

The equation is $$t = 5d$$ .

The constant of proportionality is 5, which means it takes 5 minutes for each mile.

The weight of 12 apples is 1.44 pounds.

The ratio of oil to vinegar is 3:2.

The point (1, 1.5) represents using 1 tablespoon of vinegar and 1.5 tablespoons of oil.

The formula is $$\text{Weight} = k \times \text{Number of Apples}$$ , where $$k$$ is the weight per apple.

Two quantities are in a proportional relationship if their ratios are equal.