CHARTS

Concept: Tables, charts and graphs organize information or data. Tables and charts organize data in columns and rows. Specific items of data are found where columns and rows intersect, or meet. To use a table to find information, first read all titles and labels carefully. Then find the column and row that relate to the information you need. Graphs represent data visually to compare data from different sources, show change over a period of time, and make projections about the future.

Steps for Solving Bar and Line Graph Problems

Step 1 | Read all titles and labels carefully. Find the bar(s), or column(s) that are called for in the problem.
Step 2 | Follow the bar(s) or column(s) up to the top of the bar(s) or column(s).
Step 3 | Follow the top of the bar(s) or column(s) over to the scale at the left (vertical axis) to find the number(s) you are looking for.
Step 4 | Perform the operation(s) called for in the problem using the number(s) found in Step 3.
Step 5 | Write the final answer.

Steps for Solving Circle Graph Problems

Step 1 | Read all titles and labels carefully. Find the part(s) that are called for in the problem.
Step 2 | Perform the operation(s) called for in the problem.
Step 3 | Write the final answer.

The Bar graph below shows the difference in the price of orange juice for each year from 1984 to 1993. Bar graphs include several parts. Notice the names of all the parts in the graph below.

Bar Graph Example What is the maximum range between the years 1987 and 1990?

Step 1 | Read all titles and labels carefully. Find the bar(s), or column(s) that are called for in the problem. |
Step 2 | Follow the bar(s) or column(s) up to the top of the bar(s) or column(s). |
Step 3 | Follow the top of the bar(s) or column(s) over to the scale at the left (vertical axis) to find the number(s) you are looking for. | Follow green arrows. Numbers are 3 and 4.
Step 4 | Perform the operation(s) called for in the problem using the number(s) found in Step 3. | 4 – 3 = 1
Step 5 | Write the final answer. | The maximum range between the years 1987 and 1990 is 1.

Line graphs often show changes over time with some measure on the vertical scale and time on the horizontal scale. Line graphs have two scales and often have a key as well. Points plotted on the graph connect the two scales. On this graph each point represents the temperature at a specific time. The points are then connected by a line. The line shows a trend or a pattern of change over time. For example, the line graph below shows the price of a gallon of milk from 1996 to 2005. We can use trends to make predictions of how data may change in the near future.

Line Graph Example Mary’s grandma used 6 gallons of milk per month in her family. How much did she spend from 1998 to 2002?

Step 1 | Read all titles and labels carefully. Find the bar(s), or column(s) that are called for in the problem. |
Step 2 | Follow the bar(s) or column(s) up to the top of the bar(s) or column(s). |
Step 3 | Follow the top of the bar(s) or column(s) over to the scale at the left (vertical axis) to find the number(s) you are looking for. | Follow green arrows. Numbers are 3 and 4.
Step 4 | Perform the operation(s) called for in the problem using the number(s) found in Step 3. |
| Mary’s grandma used 6 gallons of milk per month. There are 12 months in a year. 12 times 6 is 72, so she used 72 gallons of milk per year. In 1998 she spent $4.50 per gallon. In 1999 she spent $2 per gallon. In 2000 she spent $2.50 per gallon. In 2001 she spent $4.00 per gallon. In 2002 she spent $3.50 per gallon. Mary’s grandma spent $1,188.00 for milk from 1998 to 2002. | 72 x 4.50 = 324 72 x 2.00 = 144 72 x 2.50 = 180 72 x 4.00 = 288 72 x 3.50 = 252 +1188
Step 5 | Write the final answer. | $1,188.00

Circle graphs show how parts of an amount are relate to the whole amount; the entire circle equals 100%. Most circle graphs show percents, but fractions, decimals, or whole numbers can also be used. In the graph below the sections of the graph are labeled with the name of the Budget item and the percentage that will be spent on the item. The size of each section represents a fraction of the budget. For instance, a half-circle represents one half of the budget, or 50%.

Circle Graph Example Peter Pan’s budget for last year is as shown. How much was spent monthly (on average) for Electricity?

Step 1 | Read all titles and labels carefully. |
| Find the part(s) that are called for in the problem. | electricity (15%)
Step 2 | Find the number(s) you are looking for. Perform the operation(s) called for in the problem. | electricity (15%)
| Total yearly budget = $50,000. Electricity consumes 15% of the yearly budget. Electricity consumes $7,500 per year. | 50,000 x .15 = 7500
| There are 12 months in a year. Divide7500 by 12 to determine monthly consumption of electricity. | 625
Step 3 | Write the final answer. | $625 per month