The diagram shows a cube - Edexcel - GCSE Maths - Question 18 - 2020 - Paper 3
Question 18
The diagram shows a cube.
AH = 11.3 cm correct to the nearest mm.
Calculate the lower bound for the length of an edge of the cube.
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Worked Solution & Example Answer:The diagram shows a cube - Edexcel - GCSE Maths - Question 18 - 2020 - Paper 3
Step 1
Calculate the lower bound of AH
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Answer
Since AH is given as 11.3 cm correct to the nearest millimeter, we first need to determine the lower bound for this measurement.
To find the lower bound for a measurement that is rounded to the nearest millimeter, we subtract half of the rounding value from the given measurement:
The rounding value is 1 mm.
Half of this is 0.5 mm.
Thus, the lower bound of AH is:
extLowerBound=11.3extcm−0.05extcm=11.25extcm
Step 2
Find the length of an edge of the cube
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Answer
In a cube, the length of the edge (let's denote it as 's') can be related to the length of the diagonal (AH in this case) using the formula for the diagonal of a cube:
d=s3
Where 'd' is the diagonal.
Rearranging the formula to find 's':
s=3d
Using the lower bound:
s=311.25extcm≈6.5extcm
Therefore, the lower bound of the length of an edge of the cube is approximately 6.5 cm.