# Prealgebra for Two-Year Colleges/Workbook AIE/Circle and bar graphs

Circle Graphs and Bar Graphs

## Why

Circle graphs and bar graphs are often used rather than tables to display data. Graphs can give you a quick feeling for the data.

## Learning Objectives

1. Construct clear, accurate circle graphs from tables.
2. Construct clear, accurate bar graphs from tables.

## Activity

1) What does it mean for a circle graph to be “clear”?

Graph has title. Slices are labeled with categories (words) and data (numbers).

2) Construct a circle graph for the table below.

 Leading U.S Passenger Airlines Airline # of Passengers (in millions) Delta 105 United 87 American 81 Southwest 59 U.S. Airways 58 Northwest 50

a) First Look on the last page of this handout. Cut out the protractor. You will use the protractor to measure angles in your circle graph. b) Fill in the last column of the table (degrees). i) Show your calculations in the table. ii) What is a reasonable place to round off to? Why?

Round off to the ones, because I cannot estimate any better than that from the protractor.

c) Now draw the circle graph.

Title: Absence from Work Due to Carpal Tunnel Syndrome

3) Construct a circle graph for the table below.

 Where students live while attending college Living Arrangement # of students Degrees Parent’s or Guardian’s Home 320 (320 stu)/(700 stu) = N/(360°) N ≈ 165° Campus Housing 180 (180 stu)/(700 stu) = N/(360°) N ≈ 93° Off-Campus Rental 124 (124 stu)/(700 stu) = N/(360°) N ≈ 64° Own Off-Campus Housing 62 (62 stu)/(700 stu) = N/(360°) N ≈ 32° Other Arrangements 14 (14 stu)/(700 stu) = N/(360°) N ≈ 7°

a) What is the total number of students in the survey?

700

b) Use proportions to fill in the last column of the table (degrees). Show your proportions in the table. Round off to a reasonable place.

See table above

c) Now draw the circle graph.

Title ="Where students live while attending college"

4) What does it mean for a bar graph to be “clear”?

Graph has title. Axes are labeled. Axes are marked with values and category names.

5) Create a vertical bar graph for the table to the right.

 1)      Create a vertical bar graph for the table to the right.   a)      What is the smallest number?                     ``` What is the largest number? ```     What is the difference?                          b)      How many “tic marks” are there on the graph? Leading U.S Passenger Airlines Airline # of Passengers (in millions) Delta 105 United 87 American 81 Southwest 59 U.S. Airways 58 Northwest 50

a) What is the smallest number?

50

What is the largest number?

105

What is the difference?

55

b) How many “tic marks” are there on the graph?

14

Leading U.S Passenger Airlines Airline # of Passengers (in millions) Delta 105 United 87 American 81 Southwest 59 U.S. Airways 58 Northwest 50 c) If you put the smallest number at the bottom, and the largest number at the top, how much would each tic mark be worth? Show your calculation.

55 / 14 ≈ 3.928

d) Round the answer in Part (c) up to a “nice” number.

5

e) What does a “zig-zag” on the axis mean? Will you use one? Why?

A zig-zag means that you have skipped part of the axis; the numbers have jumped. I will use one because I am starting the numbers at 50, but each tic mark is only 5.

f) Make the bar graph.