In an examination worth 240 marks, a student scored 52 marks. What central…
2018
In an examination worth 240 marks, a student scored 52 marks. What central angle in a pie chart represents the student's score?
- A.
75°
- B.
78°
- C.
63°
- D.
21 2/3°
Attempted by 4 students.
Show answer & explanation
Correct answer: B
Concept
A pie chart represents a whole by a full angle of 360°. Each category receives the same fraction of 360° as its value is of the total.
Thus, for category value v and total T, the central angle is (v/T) × 360°.
Application
Let v = 52 marks and T = 240 marks.
Substitute the values: angle = (52/240) × 360°.
Reduce the fraction by 4: 52/240 = 13/60.
Compute: (13/60) × 360° = 13 × 6° = 78°.
Cross-check
Convert the angle back to a fraction of the circle: 78°/360° = 13/60.
Apply that fraction to the total marks: 240 × 13/60 = 52.
This recovers the given score, so the angle is consistent.
Therefore, the corresponding central angle is 78°.