Proportional Graphs

Are the ratios in this table all proportional?

• Yes

• No

Is this graph an example of direct variation?

• Yes

• No

Answer explanation

Graphs of direct variation (proportional) are always:

- Straight Lines

- Go through (0,0) - the origin

What is the Constant of Proportionality for Jose's data? (remember to simplify as much as possible) (don't worry about units)

Answer explanation

The constant of variation (slope for proportional graphs) is y/x (ANY y/x)

What is the Constant of Variation for Edwin's data? (remember to simplify, and don't include units in your answer this time)

What is the Constant of Proportionality for this graph?

Answer explanation

The Constant of Proportionality (like slope for proportional data sets) can b found by taking ANY y/x on the line.

Find the Constant of Proportionality for this graph. (Make sure to simplify)

The ratio of motorcycles to cars is 2/9 in the parking lot. If there are 99 vehicles in the lot, how many are motorcycles?

Find the missing value, w, in this ratio table.

(answer w=...)

What makes a graph proportional?

• Straight line

• The line goes through the origin

• Curvy line

• Straight line and the line goes through the origin

The graph shows the cost of grapes when purchased by the pound.

What is the cost for 1 pound of grapes?

• $0.70

• $1.25

• $2.00

• $1.50