Answer:
The final angle must have a measure of 124 degrees.
Step-by-step explanation:
Heptagon is polygon with seven sides.
Sum of angles of heptagon = 900°
Given:Sum of all angles and one interior angle of a heptagon is 776°.
Let the measure of interior angle be x
776° + ∠x = 900°
∠x = 900° - 776° = 124°
The final angle must have a measure of 124 degrees.