Answer:
x = 33
Explanation:
The three numbers will be a Pythagorean triple if the sum of the squares of the first two is equal to the square of the third.
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We want ...
x² +56² = 65²
x² = 65² -56² = 4225 -3136 = 1089
x = √1089 = 33
The value x = 33 will make (33, 56, 65) a Pythagorean triple.