Question

Draw a pie-diagram of the areas of continents of the world given in the following table:

Continents	Asia	U.S.S.R	Africa	Europe	Noth America	South America	Australia
Area (in million sq. km)	26.9	20.5	30.3	4.9	24.3	17.9	8.5

Answer 1

We know:
Central angle of a component = (component value/sum of component values $\times$ 360)
Here, total area in million sq km = 133.3
Thus, the central angle for each component can be calculated as follows:

Continent	Area (in million sq. km)	Sector angle
Asia	26.9	26.9/133.3 $\times$ 360 = 72.6
U.S.S.R	20.5	20.5/133.3 $\times$ 360 = 55.4
Africa	30.3	30.3/133.3 $\times$ 360 = 81.8
Europe	4.9	4.9/133.3 $\times$ 360 = 13.2
North America	24.3	24.3/133.3 $\times$ 360 = 65.6
South America	17.9	17.9/133.3 $\times$ 360 = 48.3
Australia	8.5	8.5/133.3 $\times$ 360 = 23

Now, the pie chat representing the given data can be constructed by following the steps below:
Step 1 : Draw circle of an appropriate radius.
Step 2 : Draw a vertical radius of the circle drawn in step 1.
Step 3 : Choose the largest central angle. Here the largest central angle is 81.8^o. Draw a sector with the central angle 81.8^o in such a way that one of its radii coincides with the radius drawn in step 2 and another radius is in its counter clockwise direction.
Step 4 : Construct other sectors representing other items in the clockwise sense in descending order of magnitudes of their central angles.
​Step 5 : Shade the sectors with different colours and label them, as shown as in figure below.​​