Farms in America

Materials: calculator, spreadsheet software (optional), grid paper

Work alone or in a pairs.

The table shows the approximate number of U. S. farms, in millions, and the size of farms, in acres for various years.

Source:The World Almanac

Procedure for the Activity

Step 1  Write six ordered pairs (years since 1940, number of farms). Graph the ordered pairs on a coordinate axes. Connect consecutive points with line segments. Describe the graph.

Step 2  Find the rate of change for each line segment in the graph from Step 1. List the values in a table like the one started below. What do the values for the rate of change represent in this situation?

Step 3  Find the average of the rate of change values in Step 2. Find the rate of change using only the ordered pairs (0, 6.2) and (49, 2.2). How do the values compare?

Step 4  Write six ordered pairs (years since 1940, average number of acres). Graph the ordered pairs on a coordinate axes. Connect consecutive points with line segments. Describe the graph.

Step 5  Find the rate of change for each line segment in the graph from Step 3. List the values in a table like the one started below. What do the values for the rate of change represent in this situation?

Step 6  Find the average of the rate of change values in Step 5. Find the rate of change using only the ordered pairs (0, 174) and (49, 432). How do the values compare?

Step 7  What is the relationship between the two sets of data—years versus number of farms and years versus size of farms?

Wrapping Up the Activity

Research agriculture in your state. Find out how the number of farms, size of farms, and people employed in agriculture has changed in the past decade. Write a one-page summary of your findings. Include a graph displaying some data about agriculture in your state.