Can You See Them?
Geometry
Level
3
In the 4 by 4 grid above, how many squares can be drawn using only dots from this grid of 16 evenly spaced dots as vertices?
The answer is 20.
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1 solution
First, take basic squares. 1 (4 by 4) square, 4 (3 by 3) squares, 9 (2 by 2) squares, 14 basic squares in total. Around each of the 4 centered points, there is a square, and there are 2 more squares that each use 4 points from each side of the big square. 14 + 4 + 1 + 1 = 2 0