The graph below shows the number of children and the number of adults visiting Disneyland over a 4-year period. Analyze the chart and answer the questions that follow. In 2002, if 1200 children were, by mistake, considered as adults, then by what percentage has the total visitors in 2002 affected?
Answers
Answer:
There are two approaches to constructing a pie chart from any given data.
A) Degree Approach: The central angle in a circle represents 360∘ , so any part or segment in pie chart is calculated as a proportion of 360∘.
B) Percentage Approach: In this case, any part or segment in a pie chart is calculated as a part of 100%.
If we convert the same pie chart into the degree format, we will be required to do the following conversions:
Total = 100 = 360∘
Hence = 1% = 3.6∘
Center = 10% = 36∘
North = 20% = 72∘
South = 25% = 90∘
East = 15% = 54∘
West = 30% = 108∘
Limitations of Pie Charts
Despite the pie chart being one of the most important ways to represent data, it is marred by limitations of its own:
Pie charts can be used only when the sum of all categories is given, for example if the categories represent proportions or percentage of a total.
A single pie chart can represent only one continuous variable.
Prerequisites (Related Formulas)
In pie charts, from geometry, we know that the area the sector of a circle must be proportional to the corresponding value of the component.
Since the sum of all the central angle is 360°, we have
Central angle of the component = {(value of the component/Total value) x 360} °.
Significance of Pie Charts
The pie chart has gained prominence due to the following reasons:
In a pie chart, we get a clear picture of the contribution of different sectors to the buildup of the total. E.g.., presentation of budgets.
Comparing two pie charts is easier than comparing two bar charts or any other format of data representation.
Let us see the following data :
Sale value in 2005 = Rs 180 crores
Sale value in 2006 = Rs 204 crores
Example 1: What is the presentation increase in the sales value of the East zone?
Solution: There are two percentage increase (A) Total total sales value of company XYZ is increasing. (B) The percentage contribution of the East zone is increasing.
Percentage increase in The total sales value of the company XYZ = 30%
Percentage increase in the percentage contribution of the East zone = 20%
Hence, the net percentage increase = 56%
(Successive increase of 20% and 30%)
Type of Pie Charts
There are two of pie charts :
(A) Normal Pie Chart
This displays the contribution of each component of the pic.
(B) Exploded Pie Chart
This pie chart has all the characteristics of a normal pie chart, the only addition is that the contribution of individual segments is highlighted.