The sum of the interior angles in a closed traverse is equal to:

Concept:

When the lines form a circuit that ends at the starting point, it is known as a closed traverse.

Properties of closed traverse:

The sum of measured interior angles should be equal to (2N - 4) × 90°, where N=number of sides of the traverse.

If the exterior angles are measured, their sum should be equal to (2N - 4) × 360°/n.

The algebraic sum of the deflection angles should be equal to 360°, taking the right hand and deflection angles as a positive and left-hand angle as negative.

The fore bearing of the last line should be equal to its back bearing ±180° measured from the initial station.