# 7.2 Direct and Partial Variation (Rule of 4).notebook

```7.2 Direct and Partial Variation (Rule of 4).notebook
December 09, 2012
Unit 7: Linear Relations
Lesson 2:
Direct and Partial
Variation
(Rule of 4)
Reminder:
Quiz:
Test:
Partial Variation
Example 1:
A pizza company charges \$12.00 for a large pizza, and \$1.25 for each additional topping. Model this relation using: a) a table b) a graph c) an equation
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7.2 Direct and Partial Variation (Rule of 4).notebook
December 09, 2012
Direct Variation
Example 2:
The cost of M&amp;M's at The Bulk Barn is \$1.50 per 100 grams.
Model this relation using: a) a table b) a graph c) an equation
Summary
Direct variation: A relationship between two variables in which one variable is a constant multiple of the other. an equation in the form of y = mx the graph of a direct variation is a straight line that passes through the origin.
A partial variation has an equation of the form y = mx + b, where b represents the initial value and m represents the rate of change. The graph of a partial variation is a straight line that does not pass through the origin.
Rule of 4
A relation can be represented in a variety of ways so that it can be looked at from different points of view. A mathematical relation can be described in four ways:
using words
using a diagram or a graph
using numbers
using an equation
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