**Vocabulary:**

1.

**Constant of Proportionality**- Constant value of the ratio of proportional quantities x and y. Written as y = kx, k is the constant of proportionality when the graph passes through the origin. Constant of proportionality can never be zero.

2.

**Equivalent fractions**- Two fractions that have the same value but have different numerators and denominators. Equivalent fractions simplify to the same fraction.

3.

**Multiplicative inverse**- Two numbers whose product is 1.

Example - 3/4 x 4/3 = 1.

4.

**Percent rate of change**- A rate of change expressed as a percent. Example: if a population grows from 50 to 55 in a year, it grows by (5/50) = 10% per year.

5.

**Proportion**- An equation stating that two ratios are equivalent.

6. Ratio - A comparison of two numbers using division. The ration a to b (where b does not equal 0) can be written as a to b, a/b, or a:b.

7.

**Similar figures**- Figures that have the same shape but the sizes are proportional.

8.

**Unit rate**- Ratio in which the lower term, or denominator, is 1.

9.

**Scale factor**- A ratio between two sets of measurements.