A because all the other answers do not apply what so ever
3x+2=29
3x=27
x=9
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We allow the river to expand when large volumes of water are entering our country. It's not fighting against water; it is living with water.”

1) x=9, because we can use the Pythagorean theorem, x^2 + 144 = 225, x^2 = 81
2)
, because 6^2 +6^2 = 72, 
3)
, because 
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none of them are a right angle since there isn't an angle on any of those measurements that are 90 degrees.