if the pattern shown below in the stacks of cubes continues, how many cubes will be contained in the 20th stack?

Question

1. 1 cube
2. 4 cubes
3. 9 cubes
4. 16 cubes

Answer 1

The pattern is x² where x is the stack number with x = 1 being the first (top) stack and x² is the number of blocks in that stack level:

x x²

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1 1² = 1

2 2² = 4

3 3² = 9

4 4² = 16

...

20 20² = ???