Answer:
4
Explanation:
If all were measure 5, the perimeter would be 30. The perimeter is 4 more than that. Each side that is 6 instead of 5 adds 1 to the perimeter, so there are 4 sides of length 6.
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Check
2×5 + 4×6 = 10 + 24 = 34 . . . . the answer checks OK