We know that the interior angle sum of a polygon is (n − 2) × 180°, where n is the number of sides.
Here, number of sides (n) = 12
So, interior angle sum = (n − 2) × 180°
=> interior angle sum = (12 - 2) × 180°
=> interior angle sum = 10 × 180°
=> interior angle sum = 1800°
So, the interior angle sum of this polygon is 1800°.