#### Question

The following table shows how a student spends his pocket money during the course of a month. Represent it by a pie-diagram.

Items | Food | Entertainment | Other expenditure | Savings |

Expenditure | 40% | 25% | 20% | 15% |

#### Solution

We know:

Central angle of a component = (component value/sum of component values x 360)

Here, total expenditure = 100%

Thus, central angle for each component can be calculated as follows:

Item |
Expenditure(in %) |
Sector angles |

Food | 40 | 40/100 x 360 = 144 |

Entertainment | 25 | 25/100 x 360 = 90 |

Other expenditures | 20 | 20/100 x 360 = 72 |

Savings | 15 | 15/100 x 360 = 54 |

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 144^{o}. Draw a sector with the central angle 144^{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 the 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.