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Ladder and Cube
A 1 metre cube has one face on the ground and one face against a wall. A 4 metre ladder leans against the wall and just touches the cube. How high is the top of the ladder above the ground?
Bendy Quad
Four rods are hinged at their ends to form a convex quadrilateral. Investigate the different shapes that the quadrilateral can take. Be patient this problem may be slow to load.
Age 14 to 16
Challenge Level
21
Why?
Adding 30 to the age 15 years ago is the same as squaring it
| Number | Square | Difference |
|---|---|---|
| 3 | 9 | 6 |
| 4 | 16 | 12 |
| 5 | 25 | 20 |
| 6 | 36 | 30 |
| 7 | 49 | 42 |
The difference keeps getting bigger so 6 is the only solution
I was 6 15 years ago, so now I am 21
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NRICH is part of the family of activities in the Millennium Mathematics Project.
NRICH is part of the family of activities in the Millennium Mathematics Project.