LESSON 1-DISCUSSION

​Direct Variation

​Direct variation is used in many every day life applications. One example is distance; d=rt is just one example of a direction variation.

Multiple Choice

  What happens to the number of points when the number of kilograms of paper is doubled?

• A. INCREASES

• B. DECREASES

• C. NEITHER

Open Ended

  In what wat are you able to help clean the environment by collecting these papers? What items can be made out of these papers?

Direct Variation defined

In mathematical sentence, it will be " when x is increases y also increases or if y is decreseases, x also decreases " and the ratio between them is constant or the same for all given values of the variables.

In mathematical sentence, it will be " when x is increases y also increases or if y is decreseases, x also decreases " and the ratio between them is constant or the same for all given values of the variables.

Constant of Variation

In the formula, y=kx, k is referred to as the constant of variation or the constant of proportionality. It is the coefficient of x (not y!)

A constant does not change in value.

The statements:

“y varies directly as x”

“y is directly proportional to x”

“y is proportional to x”

      Are translated mathematically as y=kx, where k is the constant of variation, x is the independent variable and y is the dependent variable.

LETS BACK!

How many kilograms of papers will the Grade9 Lavender class have in order to raise 600 points?


solve this by using the formula of direct variation.

Multiple Choice

What happens to the distance as the length of time increases?

• A. INCREASES

• B. DECREASES

• C. NEITHER

Open Ended

If x varies directly as y and x=35 when y=7, what is the value of y when x=25