Pie Charts — Degrees, Percentage & Value
Pie Charts — Degrees, Percentage और Value
Pie Charts — Degrees, Percentage & Value
- Data Interpretation
- Pie Charts — Degrees, Percentage & Value
Convert freely between the three languages of a pie chart: central angle (degrees), percentage share, and actual value.
🎯 Learning Objective
Convert freely between the three languages of a pie chart: central angle (degrees), percentage share, and actual value.
💡 Concept
- A full pie = 360° = 100% = the whole total value
- So 1% = 3.6°, and 1° = (100/360)% of the total
- Percentage → Degrees: multiply by 3.6
- Degrees → Percentage: divide by 3.6
- Value of a sector = (its % ÷ 100) × Total = (its degrees ÷ 360) × Total
🧮 Key Formulas
Degrees = Percentage × 3.6
>
Percentage = Degrees ÷ 3.6
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Value = (Percentage ÷ 100) × Total
✏️ Easy Example
Q. A family's monthly budget of ₹36,000 is shown as a pie chart: Food 30%, Rent 25%, Education 20%, Savings 15%, Others 10%. Find the central angle (in degrees) of the Food sector.
- Food = 30%
- Degrees = 30 × 3.6
Answer: 108°
🇮🇳 Real-Life Example
Every Budget-day newspaper prints 'where each rupee comes from and goes' as a pie. When it says defence is 72° of the circle, that's exactly 20% of the whole budget — same maths as this lesson.
📝 Exam-Level Example
Q. From the same pie (Total ₹36,000, Rent = 25%), how much money is spent on Rent?
- Value = (25 ÷ 100) × 36000
- = 0.25 × 36000
Answer: ₹9,000
📝 Exam-Level Example
Q. In the same pie, the Education sector has a central angle of 72°. What percentage is that, and how much money is it (Total ₹36,000)?
- Percentage = 72 ÷ 3.6 = 20%
- Value = (20 ÷ 100) × 36000 = ₹7,200
Answer: 20%, i.e. ₹7,200
📝 Exam-Level Example
Q. How much more money is spent on Food (30%) than on Savings (15%) from the ₹36,000 total?
- Food = 30% of 36000 = ₹10,800
- Savings = 15% of 36000 = ₹5,400
- Difference = 10800 − 5400
Answer: ₹5,400
🪄 Memory Trick
Memorise one bridge: 1% = 3.6°. Everything (percentage, angle, value) then converts through it in a single multiply or divide.
⚠️ Common Mistakes
- ❌ Using 360 instead of 3.6 when converting percentage to degrees
- ❌ Taking value as a % of 360 instead of the total money
- ❌ Assuming the sectors don't add to 100% (they always do)
🏆 Exam Tips
- ✅ Check your sectors add to 100% (and 360°) as a sanity test
- ✅ Value can be found via % OR via degrees/360 — both give the same answer
📌 Summary
- Whole pie = 360° = 100% = total value
- 1% = 3.6° is the master bridge
- % → degrees: ×3.6; degrees → %: ÷3.6
- Value = (% ÷ 100) × Total = (degrees ÷ 360) × Total