Pie Charts and Mixed DI

A pie chart's full circle = 360° = 100% of the total. Conversion: 1% = 3.6°, and 1° = 5/18 %. To find a sector's value: (sector % or sector°/360) × total. SBI PO often gives ONE pie in degrees and another in percentages, or a pie plus a table — convert everything to a common unit first. Key memory aids: 90°=25%, 45°=12.5%, 60°=16.67%, 72°=20%, 36°=10%, 120°=33.33%, 180°=50%. To find the total when one sector's value and its angle are known: total = value × 360/angle. For 'central angle of X' questions: angle = (X value/total) × 360. Always confirm whether the question wants degrees, percent, or absolute value.

Mixed (or 'combined') DI pairs a pie with a bar, table, or line — or gives two interlinked charts. The skill tested is data transfer: a value from chart 1 becomes the base for chart 2. Workflow: (1) compute the grand total from whichever chart gives absolute figures; (2) convert all sectors/series to absolute values; (3) only then answer. Trap: percentages in two different charts are taken on DIFFERENT bases — never add raw percentages across charts. For 'X in chart A as % of Y in chart B', compute both absolute values first. Time tip: in a 5-question mixed set, the first 2 minutes spent building a small absolute-value table pays back across all questions.

A pie shows a family's monthly budget of Rs 48,000 split as: Food 30%, Rent 25%, Education 20%, Savings 15%, Misc 10%. Food = 30% × 48000 = Rs 14,400. Education = 20% × 48000 = Rs 9,600. 'Central angle of Rent' = 25% × 360 = 90°. 'Rent is how much more than Misc': Rent 12,000 − Misc 4,800 = Rs 7,200, or as % = (25−10)/10 × 100 = 150% more. If a second pie splits Food into items, multiply: e.g. Vegetables = 40% of Food = 0.40 × 14,400 = Rs 5,760. Note the chained calculation — Food's value feeds the sub-pie.

Cover the answer, recall, then check. 12 cards on pie charts and mixed DI for SBI PO.

Q1. Convert 108° to a percentage.
A1. 108 ÷ 3.6 = 30%. (1% = 3.6°.)

Q2. Convert 20% to degrees.
A2. 20 × 3.6 = 72°.

Q3. Value of a 25% slice of a total of 7,200?
A3. 7,200 × 0.25 = 1,800.

Q4. How many degrees is 1%?
A4. 3.6° (because 360° = 100%).

Q5. A 90° slice is what percent?
A5. 90 ÷ 3.6 = 25%.

Q6. Two pies with DIFFERENT totals — can you compare slices by percentage?
A6. No. Convert each slice to its absolute value first; 20% of 9,000 (1,800) beats 30% of 5,000 (1,500).

Q7. Central angle for a category worth 15%?
A7. 15 × 3.6 = 54°.

Q8. Slice value from degrees: total 7,200, slice 54°?
A8. 7,200 × 54/360 = 7,200 × 0.15 = 1,080.

Q9. The anchor: 60° equals what percent?
A9. 60 ÷ 3.6 = 16.67% (= 1/6).

Q10. Ratio of two slices, 30% and 20%?
A10. 3 : 2 — compare percentages (or degrees) directly, no need for values.

Q11. The mixed-DI workflow in one line?
A11. Find the total → convert the needed slice to a value → carry that value into the second chart/table as its new total.

Q12. A 36° slice is what percent?
A12. 36 ÷ 3.6 = 10%.

Pie-chart DI tests one thing above all: converting between degrees, percentages, and absolute values. SBI PO loves "mixed" sets — a pie plus a table, or two linked pies (distribution plus a sub-breakup) — where you must move a value from one chart into another. Expect at least one pie/mixed set in Mains and often one in Prelims.

The three currencies of a pie

• The whole circle = 360° = 100% = the given total.
• 1% = 3.6°, so degrees ÷ 3.6 = percent, and percent × 3.6 = degrees.
• Value of a slice = Total × (slice % / 100) = Total × (slice degrees / 360).

Mixed-DI workflow

1. Find the total (usually given for one pie).
2. Convert the needed slice to an absolute value.
3. Carry that value into the second chart/table as its new total.

Category	Degrees	Percent	Value (Total = 7200)
Food	108	30%	2160
Rent	90	25%	1800
Travel	54	15%	1080
Savings	72	20%	1440
Other	36	10%	720

Example: 108 ÷ 3.6 = 30%; 30% of 7200 = 2160. If a second pie splits Savings (1440) in the ratio 5 : 3, the parts are 900 and 540.

Exam Tricks & Tips

• 🎯 Memorise the anchors: 90° = 25%, 72° = 20%, 60° = 16.67%, 54° = 15%, 45° = 12.5%, 36° = 10%.
• 🎯 Use degrees ÷ 3.6 for percent — faster than setting up a fresh proportion each time.
• 🎯 In two-pie sets, confirm whether both pies share the same total or have different totals before combining.
• 🎯 To compare two slices of the SAME pie, compare their degrees/percentages directly — no need for values.
• 🎯 For "central angle" questions, go value → percent → × 3.6.
• ❌ Don't compare slice percentages across two pies with different totals — convert each to a value first; 20% of 9000 (1800) beats 30% of 5000 (1500).

Expected exam pattern

One pie with a given total, or two linked pies; asks for a slice's value, the central angle of a category, the ratio of two slices, and a "combined with the table" cross-value.

Quick recap

360° = 100% = total; 1% = 3.6°. Convert a slice into a value before crossing into any second chart, and never compare percentages across pies that have different totals.