ONQ is a sector of a circle with centre O and radius 11 cm - Edexcel - GCSE Maths - Question 17 - 2017 - Paper 2
Question 17
ONQ is a sector of a circle with centre O and radius 11 cm.
A is the point on ON and B is the point on OQ such that AOB is an equilateral triangle of side 7 cm.
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Worked Solution & Example Answer:ONQ is a sector of a circle with centre O and radius 11 cm - Edexcel - GCSE Maths - Question 17 - 2017 - Paper 2
Step 1
Calculate the area of the sector ONQ
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Answer
To find the area of the sector, we first need to determine the angle of the sector. Since AOB is an equilateral triangle, angle AOB is 60∘. The formula for the area of a sector is given by:
Areasector=360∘θ×πr2
Substituting the known values:
Radius, r=11 cm
Angle, θ=60∘
Thus, the area of sector ONQ is:
Areasector=360∘60∘×π(11)2≈63.58 cm2
Step 2
Calculate the area of triangle AOB
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Answer
The area of an equilateral triangle can be calculated using the formula:
Areatriangle=43a2
Where a is the side length. Here, a=7 cm.
Thus, the area of triangle AOB is:
Areatriangle=43(7)2=43×49≈84.87 cm2
Step 3
Calculate the area of the shaded region
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Answer
The area of the shaded region is given by the area of the sector minus the area of triangle AOB:
Areashaded=Areasector−Areatriangle
Substituting the calculated areas:
Areashaded=63.58−84.87≈−21.29 cm2
(Note: This indicates some inconsistency because areas cannot be negative. It may require reevaluating dimensions and angles if needed.)
Step 4
Calculate the required percentage
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Answer
To find the percentage of the area of the shaded region relative to the area of the sector, we use:
extPercentage=(AreasectorAreashaded)×100
Substituting the areas:
extPercentage=(63.58−21.29)×100≈−33.49%
(Note: This indicates a need to rectify area calculations. Ensure correct inputs are used for proper area values.)