★Answer
As We know a heptagon has 7 sides. So , we take the hexagon's sum of interior angles and add 180 to it getting us, 720+180=900 degrees.
So Here,
⇢ 129° + 116 °+ 120° +130° + 135 °+ 125° + y = 900°
⇢755° +y = 900°
⇢y = 900 °- 755°
⇢y = 145°
Hence, The Answer is 145°
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