Line Graphs:
* A line graph is preferred when we want to observe a rising or falling trend in a set of data over a period of time. To obtain a line graph, we can plot the points on a graph paper and connect each successive point by line segments.
* An advantage of a line graph is that intermediate values can be easily obtained while a disadvantage values may not be meaningful.
* A line graph is most suitable when we want to show trends over a period of time.
Problem involving a Line Graph:
Q.2. The line graph shows the rubber consumption of the automobile industry in a country from January to May of a particular year.
i) In which month was the rubber consumption the lowest?
ii) Using data from the line graph, construct a table showing the rubber consumption over the five months.
iii) Calculate the percentage increase in the rubber consumption from February to March.
iv) Suggest a reason for the increase in rubber consumption from February to March.
Solution:
i) The rubber consumption was the lowest in May.
iii) Percentage increase in the rubber consumption from
February to March = 200-155/155 X 100%
= 29%
iv) The increase in rubber consumption from February to March may be caused by an increase in sales as more rubber tyres were needed for the production of more vehicles.
Q.2. The line graph shows the number of total road casualties in each year from 2005 to 2009.
i) In which year was the number of fatal road casualties the highest?
ii) Using data from the line graph, construct a table showing the number of fatal road casualties over the five years.
iii) Find the percentage decrease in the number of fatal road casualties from 2008 to 2009.
iv) Suggest a reason for the decrease in the number of fatal road casualties from 2008 to 2009.
Solution:
i) The number of fatal road casualties was the highest was 2008.
ii)
Year 2005 2006 2007 2008 2009
Number of
fatal road 172 190 214 221 184
casualties
Q.3. The line graph shows the number of fatal road casualties in each year from 2005 to 2009.
i) In which year was the number of fatal road casualties the highest?
Ans: 2008
ii) Using data from the line graph, construct a table showing the number of fatal road casualties over the five years.
Solution:
Year ---- 2005 --- 2006 -- 2007 --- 2008--- 2009
Number of fatal road -- 172 --- 190 -- 214 --- 220 --- 182
Ans: 17 43/221
iii) Find the percentage decrease in the number of fatal road casualties from 2008 to 2009.
Solution:
220 - 182 /182 x 100%
= 38 x 100 / 182
= 476/23
iv) Suggest a reason for the decrease in the number of fatal road casualties from 2008 to 2009.
Q.4. The line graph shows the mass of a baby from birth to 6 months.
Baby's Mass from Birth to 6 Months
i) Using data from the line graph, construct a table showing the mass of the baby from birth to 6 months.
ii) Find the percentage increase in the mass of the baby from the 4th to the 6th month.
Ans: 19 1/21
Q.5. The line graph shows the number of people in a town in each year from 2002 to 2012.
i) Between which two years did the town have the greatest increase in the number of people?
Ans: 2011 2012
ii) Using data from the line graph, construct a table showing the number of people in the town over the 11 years.
Ans: 25,000
iii) Find the percentage increase in the number of people in the town from 2009 to 2012.
Ans: 56 1/4
iv) Suggest a reason for the sudden increase in the number of people in 2012.
Q.6. The line graphs show the average temperatures of two countries X and Y in each month from January to June.
Nora says that the temperatures in Country X change more drastically than those in Country Y. Do you agree with her? Explain your answer.
Ans: No