The length of the longest diagonal of a cube is 25 cm - OCR - GCSE Maths - Question 14 - 2019 - Paper 6
Question 14
The length of the longest diagonal of a cube is 25 cm.
Calculate the total surface area of the cube.
Worked Solution & Example Answer:The length of the longest diagonal of a cube is 25 cm - OCR - GCSE Maths - Question 14 - 2019 - Paper 6
Step 1
Calculate the side length of the cube
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Answer
The diagonal of a cube can be calculated using the formula:
d=asqrt3,
where d is the diagonal and a is the side length of the cube.
Given that the diagonal d=25 cm, we can rearrange this formula to solve for a:
a=sqrt3d=sqrt325≈14.43 cm.
Step 2
Calculate the total surface area of the cube
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Answer
The total surface area (S) of a cube can be calculated using the formula:
S=6a2.
Substituting the value of a we found:
S=6×(14.43)2≈1249.74 cm2.
Rounding to the nearest whole number gives us approximately 1250 cm².