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# A Grade GCSE Maths Question Help Watch

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1. Carla has made a cube out of cardboard. Each side of the cube is 12.5cm long. Carla suspends the cube from the ceiling by one corner. How far below the top corner is the bottom corner. The answer is 21.7cm. I realise I need to do Pythagoras theorem but I keep getting the wrong answer... Help please
2. When you have a cube or cuboid and want to find a diagonal length like this, it is very simple. You only need to do each length of the square, squared and added together.
a² + b² = c²
It looks more like:
a² +b² + c² = d² (though I don't think this is the correct notation, you should get the idea)
So you need to do 12.5² x 3, (since each side is the same) and then square root it.
12.5² = 156.25
156.25 x 3 = 468.75
If you square root this it comes out as 21.65 which rounds to 21.7
3. (Original post by sometwat)
When you have a cube or cuboid and want to find a diagonal length like this, it is very simple. You only need to do each length of the square, squared and added together.
a² + b² = c²
It looks more like:
a² +b² + c² = d² (though I don't think this is the correct notation, you should get the idea)
So you need to do 12.5² x 3, (since each side is the same) and then square root it.
12.5² = 156.25
156.25 x 3 = 468.75
If you square root this it comes out as 21.65 which rounds to 21.7
Thank you so much x

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