ABCDEF GH is a cuboid - Edexcel - GCSE Maths - Question 20 - 2022 - Paper 2

Question 20

ABCDEF GH is a cuboid.
AD = 9cm
FD = 13cm
Angle GHF = 49°.
Work out the size of angle FAH.
Give your answer correct to the nearest degree.
Worked Solution & Example Answer:ABCDEF GH is a cuboid - Edexcel - GCSE Maths - Question 20 - 2022 - Paper 2
Step 1: Identify the triangle of interest

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In triangle FAH, we know the lengths of AD and FD as well as the angle GHF. We can label the sides accordingly:
- AD = 9 cm
- FD = 13 cm
- Angle GHF = 49°
Step 2: Use the sine rule or cosine rule

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Since we have two sides and the angle between them, we can use the cosine rule to find angle FAH, which can be labeled as θ:
heta=extangleFAH
Using the cosine rule:
c2=a2+b2−2abimesextcos(C)
Where:
- c = AF
- a = AD
- b = FD
- C = ext{angle GHF}
Calculating side AF:
a = AD = 9,
b = FD = 13,
C = 49°,
We can substitute these values into the formula.
Step 3: Calculate the angle FAH

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After calculating the value of c using the cosine rule, we can find the angle FAH. Alternatively, we can use the sine rule to directly find angle θ:
sin(49°)AD=sin(θ)FD (using sine rule)
This can be solved for θ to find angle FAH.
Step 4: Final answer

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After performing the calculations, you would find angle FAH, rounded to the nearest degree.
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