Consider the following arrangement of 25 points.
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Gastón must choose 4 of these points.
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The chosen points must be the vertices of a square.
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In how many ways can this be done?
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Solution
The following figures show how many squares of each type Gastón can choose.
(a) 1 square
(b) 16 squares
(c) 9 squares
(d) 4 squares
(e) 9 squares
(f) 4 squares
(g) 4 squares
(h) 2 squares
(i) 1 square
The total number of squares is 50.
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