- LPU MCA Semester 1
- PEA515
- Unit 7
PEA515 · Unit 7: Data interpretation
Pie charts
30 practice questions · in the ETE syllabus
Key points
- 100 percent = 360 degrees, so 1 percent = 3.6 degrees
- Value = percentage x total / 100
- Value from angle = angle / 360 x total
- Sector ratios equal percentage or angle ratios
A pie chart divides a circle into sectors that show shares of a total. The whole circle is 100 percent and 360 degrees, so
1% = 3.6 degrees and angle = percentage x 3.6.
| Question | Method |
|---|---|
| Value of a sector | Percentage / 100 x total |
| Central angle of a sector | Percentage x 3.6 |
| Value from an angle | Angle / 360 x total |
| Difference of two sectors | Difference of percentages x total / 100 |
| Ratio of two sectors | Ratio of their percentages (or angles), reduced |
Example: with a total of 36000 and English at 35%, the value is 36000 x 35 / 100 = 12600. A 10% sector has an angle of 36 degrees. A sector of 72 degrees out of 360 is 20% of the total, so with a total of 5000 it is 1000.
Sector values are proportional to their percentages and their angles, so ratios can be taken straight from either, and the percentages must add up to 100 (the angles to 360).
Exam trap: convert the angle with 360, not with 100, and subtract percentages before taking the share of the total.