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Area of a segment Quiz

Grade 7 • 7U • 10 Questions (41 Marks)

Score: 0 / 10
Area of a segment — Notes & Worked Examples Show / Hide

Explanation:

A segment is the region enclosed between a chord and an arc of a circle. To find the area of a minor segment with radius r and central angle θ, subtract the area of the isosceles triangle formed by the two radii and the chord from the area of the sector:

Area of segment = Area of sector − Area of triangle = (θ360 × πr2) − (12r2 sin θ). To find the perimeter of a segment, add the arc length (θ360 × 2πr) to the chord length (found using the Cosine Rule).

Example 1: Find the area of the minor segment of a circle with radius 10 cm and central angle 72° (3 s.f.).

O 72° 10 cm 10 cm Minor segment

Solution:

Area of sector = 72360 × π × 102 = 20π = 62.8318... cm2
Area of triangle = 12 × 102 × sin 72° = 47.5528... cm2
Segment area = 62.8318... − 47.5528... = 15.2790...
Answer: 15.3 cm2 (3 s.f.)

Example 2: Find the exact area of a minor segment with radius 6 cm and central angle 60°.

Solution:

Area of sector = 60360 × π × 62 = 6π cm2
Area of triangle = 12 × 62 × sin 60° = 18 × √32 = 9√3 cm2
Subtract triangle from sector:
Answer: (6π − 9√3) cm2
Question 1
[2 marks]
60°12 cmOAB
The diagram shows a sector OAB of a circle with radius 12 cm and angle 60°.
Calculate the area of the shaded segment correct to 2 decimal places.
cm²
Worked Solution & Answer
(The area of a sector is (angle ÷ 360°) × πr²)
Area = 60360π(122) - 12(122)\sin(60°) = 13.04 cm2 B1
Answer: 13.04 cm2 cm²
Question 2
[2 marks]
60°8 cmOAB
The diagram shows a sector OAB of a circle with radius 8 cm and angle 60°.
Calculate the area of the shaded segment correct to 2 decimal places.
cm²
Worked Solution & Answer
(The area of a sector is (angle ÷ 360°) × πr²)
Area = 60360π(82) - 12(82)\sin(60°) = 5.8 cm2 B1
Answer: 5.8 cm2 cm²
Question 3 Specimen Set 2 2H Q7
[3 marks]
ABCO4.8 cm
The arc ABC is a quarter of a circle with centre O and radius 4.8 cm.
AC is a chord of the circle.
Work out the area of the shaded segment.
Give your answer correct to 3 significant figures.
The arc ABC is a quarter of a circle with centre O and radius 4.8 cm.
AC is a chord of the circle.
Work out the area of the shaded segment.
Give your answer correct to 3 significant figures.
cm²
Worked Solution & Answer
(The area of a circle is πr²)
Area of quarter circle = ¼ × π × 4.8² = 5.76π ≈ 18.0956 cm² M1
Area of triangle OAC = ½ × 4.8 × 4.8 = 11.52 cm² M1
Shaded segment = 18.0956 – 11.52 = 6.58 cm² (3 s.f.). A1
Answer: 6.58 cm²
Question 4
[4 marks]
The diagram shows a sector OPQR of a circle, centre O and radius 8 cm.
OPRQ8 cm8 cm
OPR is a triangle.
Work out the area of the shaded segment PQR.
Give your answer correct to 3 significant figures.
cm²
Worked Solution & Answer
(The area of a triangle is ½ × base × height)
Area of sector = ¼ × π × 8² = 16π ≈ 50.265 cm² M2
Area of triangle OPR = ½ × 8 × 8 = 32 cm² M1
Segment = 50.265 – 32 = 18.3 cm² (3 s.f.) A1
Answer: 18.3 cm²
Question 5 IGCSE Jan 2022 2F Q5
[4 marks]
The diagram shows points A and B marked on a grid of squares.
yxO−5−4−3−2−11234567−3−2−1123456AB
(a) On the grid, draw the line with equation y = -2 [1 mark]
(b) Find the coordinates of M [2 marks]
(c) Find the value of d [1 mark]
d =
Worked Solution & Answer
(a)
Horizontal line through (0, –2) B1
Answer (a): Horizontal line drawn at y = −2
(b)
((–3 + 1)/2, (1 + 3)/2) = (–1, 2) M1 A1
Answer (b): (-1, 2)
(c)
AB² = 4² + 2² = 20
for BD = AB with xD = 5 (4 units right of B), yD = 3 – 2 = 1 ⇒ d = 1 B1
Answer (c): d = 1
Question 6 IGCSE Jan 2023 1H Q21
[5 marks]
The diagram shows the cross section of a circular water pipe.
72°4.8 cmOABCDiagram NOTaccurately drawn
OABC is a sector of the circle, centre O
The shaded region in the diagram represents the water flowing in the pipe.
The water flows at 14 cm/s in the pipe.
Work out the volume of water that has flowed through the pipe in 3 minutes.
Give your answer in cm3 correct to 3 significant figures.
cm³
Worked Solution & Answer
Area of sector OABC = (72/360) × π × 4.8² = 14.47645... cm² M1
Area of triangle OAC = ½ × 4.8² × sin 72° = 10.95617... cm² M1
Area of shaded segment = 14.47645... − 10.95617... = 3.52028... cm² M1
In 3 minutes (180 seconds), length of flow = 14 × 180 = 2520 cm M1
Volume = 3.52028... × 2520 = 8871.1... ≈ 8870 cm³ (3 s.f.). A1
Answer: 8870 cm³
Question 7 IGCSE Jan 2023 2H Q14
[5 marks]
A, B, C and D are points on a circle, centre O
EBF is the tangent to the circle at B
O40°66°ADCBEFDiagram NOTaccurately drawn
(a) Work out the size of angle DCB [1 mark]
°
(b) Give a reason for your answer to (a)(i) [1 mark]
(b) Work out the size of angle ADO [3 marks]
°
Worked Solution & Answer
(a)
180° − 40° = 140° (opposite angles of a cyclic quadrilateral sum to 180°) B1
Answer (a): 140 °
(b)
Opposite angles of a cyclic quadrilateral sum to 180°
Answer (b): Opposite angles of a cyclic quadrilateral sum to 180°
(b)
Angle DOB = 2 × 40° = 80° (angle at centre) M1
Since OD = OB, angle ODB = (180° − 80°)/2 = 50° M1
By alternate segment theorem, angle ADB = angle ABF = 66°
Therefore angle ADO = 66° − 50° = 16° A1
Answer (b): 16 °
Question 8 IGCSE Jun 2018 2F Q9
[5 marks]
R and S are points on a circle with centre O.
ORS
(a) On the diagram above, shade a segment of the circle. [1 mark]
(b) Write down the mathematical name of the straight line RS. [1 mark]
(c) QT is a tangent to the circle.
Angle OPQ = 18°
Work out the size of angle PQT.
Give a reason for each stage of your working.
[3 marks]
18°OPQT
°
Worked Solution & Answer
(a)
Region between chord RS and arc RS shaded
Answer (a): Region between chord RS and arc RS shaded
(b)
Chord
Answer (b): Chord
(c)
Angle OQP = 18° (base angles of isosceles triangle OPQ are equal as OP = OQ) M1
Angle OQT = 90° (angle between tangent and radius is 90°) M1
Angle PQT = 90° – 18° = 72° A1
Answer (c): 72 °
Question 9 IGCSE Jun 2024 1FR Q9
[5 marks]
The diagram shows three points, A, B and C, marked on a grid.
xyO−5−4−3−2−112345−4−3−2−11234ABC
(a) Write down the coordinates of A [1 mark]
(b) Find the coordinates of the midpoint of AB [2 marks]
(c) Find the coordinates of D [2 marks]
Worked Solution & Answer
(a)
A = (−4, 2) B1
Answer (a): −4, 2
(b)
Midpoint = ((−4+2)/2, (2+4)/2) = (−1, 3) M1 A1
Answer (b): −1, 3
(c)
D = A + (C − B) = (−4 + 1, 2 − 3) = (−3, −1) M1 A1
Answer (c): −3, −1
Question 10 IGCSE Jun 2025 1HR Q25
[6 marks]
BAC is a sector of a circle, centre A
BCD is a sector of a circle, centre C
ABCDDiagram NOTaccurately drawn
Angle BAC = 40°
Angle BCD = 130°
Area of shaded segment = 28 cm2
Find the length of the arc BD
Give your answer correct to 3 significant figures.
cm
Worked Solution & Answer
(The area of a sector is (angle ÷ 360°) × πr²)
Area of segment = (40/360)πr² − (1/2)r² sin 40° = 28 ⇒ r²(0.349066 − 0.321394) = 28 ⇒ r² = 1011.86 ⇒ r = 31.81 cm M3
Chord BC = 2 × 31.81 × sin 20° = 21.759 cm M2
Arc BD = (130/360) × 2π × 21.759 = 49.37... = 49.4 cm (3 s.f.). A1
Answer: 49.4 cm
Score: 0 / 10 (0 / 41 marks)
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