Figure 2 shows a plan view of a garden - Edexcel - A-Level Maths Pure - Question 6 - 2013 - Paper 4
Question 6
Figure 2 shows a plan view of a garden.
The plan of the garden ABCDEA consists of a triangle ABE joined to a sector BCDE of a circle with radius 12m and centre B.
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Worked Solution & Example Answer:Figure 2 shows a plan view of a garden - Edexcel - A-Level Maths Pure - Question 6 - 2013 - Paper 4
Step 1
(a) the area of the garden, giving your answer in m², to 1 decimal place.
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Answer
To find the area of the garden, we need to calculate the area of triangle ABE and the area of the sector BCDE separately.
Area of Triangle ABE:
The formula for the area of a triangle is:
extArea=21×a×b×sin(C)
where ( a = 23,m ), ( b = 12,m ), and ( C = 0.64 \text{ radians} ).
Substituting the values:
extArea=21×23×12×sin(0.64)
Calculating this gives:
Area≈82.4m2 (to 1 decimal place).
Area of Sector BCDE:
The formula for the area of a sector is:
extArea=21r2θ
where ( r = 12,m ) and ( \theta = 0.64, ext{radians} ).
Substituting the values:
Area≈21×122×0.64≈38.4m2.
Total Area of the Garden:
Total Area≈82.4+38.4≈120.8m2
Thus, the area of the garden is approximately 120.8 m².
Step 2
(b) the perimeter of the garden, giving your answer in metres, to 1 decimal place.
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Answer
The perimeter of the garden consists of three parts: the length AB, the radius BC, and the arc length of sector BCDE.
Length AB:
Given as ( AB = 23,m ).
Length BC:
Given as ( BC = 12,m ).
Arc Length of Sector BCDE:
The arc length can be calculated using the formula:
L=rθ
where ( r = 12,m ) and ( \theta = 0.64 \text{ radians} ).
Substituting the values gives:
L=12×0.64≈7.68m.
Total Perimeter of the Garden:
extPerimeter=AB+BC+L=23+12+7.68≈42.68m
Thus, the perimeter of the garden is approximately 42.7 m (to 1 decimal place).