128.5714286 degrees
Any angle that you like.
128.57 degrees
60 degrees
51.428571° is the measure of an exterior angle of a heptagon. You can always find the measurements of a regular polygon by dividing 360 by the amount of sides.
Each interior angle is approximately 128.57 * * * * * That is only true of a REGULAR heptagon. The question does not state that it is regular.
A heptagon has 7 sides and 7 angles. The sum of the interior angles is 900°. If the heptagon is a regular heptagon, meaning all sides and angles are congruent, then the formula (180(n-2))/ n gives the individual interior angle measure. "n" is the number of sides in this case. In a regular heptagon, the interior angle measures 128 4/7 degrees.
An interior angle of a heptagon can have any value in the range (0, 360) degrees - other than 180 degrees.
128.571428 repeating
An interior angle of a convex heptagon can have any value in the range (0, 180) degrees.
It is 900/7 = 128.57 degrees (approx).
51 degrees
360/7 = 51.43 degrees (approx).