A heptagon has seven sides. The measure of the final interior angle of the heptagon is 124°.
<h3>What is heptagon?</h3>
A heptagon, sometimes known as a septagon, is a seven-sided polygon. The heptagon is also known as the septagon, which combines the prefix "sept-" with the Greek suffix "-agon," which means "angle."
A heptagon has 7 sides therefore, the sum of the interior angle of the heptagon can be written as,

As it is said in the problem that the sum of the all the angles of the heptagon except one is 776°, therefore, the measure of the last angle of the heptagon is,
The measure of the last angle = 900° - 776° = 124°
Hence, the measure of the final interior angle of the heptagon is 124°.
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