*Created by Tiago Hands. Graphs can be reproduced @http://www.graphfree.com.*

**y is directly proportional to x.**

1. Using the proportionality symbol, we can say that **y∝x**.

2. The formula which is related to the graph above can be written like so **y=kx**. ‘k’ is the constant of proportionality.

**y is directly proportional to x squared.**

1. Using the proportionality symbol, we can say that **y∝x²**.

2. The formula which is related to the graph above can be written like so **y=kx²**. ‘k’ is the constant of proportionality.

**y is directly proportional to x cubed.**

1. Using the proportionality symbol, we can say that **y∝x³**.

2. The formula which is related to the graph above can be written like so **y=kx³**. ‘k’ is the constant of proportionality.

**y is inversely proportional to x squared.**

1. Using the proportionality symbol, we can say that **y∝1/x²**.

2. The formula which is related to the graph above can be written like so **y=k/x²**. ‘k’ is the constant of proportionality.

**y is inversely proportional to x.**

1. Using the proportionality symbol, we can say that **y∝1/x**.

2. The formula which is related to the graph above can be written like so **y=k/x**. ‘k’ is the constant of proportionality.

**y is directly proportional to the square root of x.**

1. Using the proportionality symbol, we can say that **y∝√x**.

2. The formula which is related to the graph above can be written like so **y=k√x**. ‘k’ is the constant of proportionality.