In the adjoining figure ∠A + ∠B + ∠C + ∠D + ∠E + ∠F =?

In ΔACE
∠A + ∠C + ∠E = 180°
Similarly in ΔDFB
∠D + ∠F + ∠B = 180°
∴ (∠A + ∠C + ∠E) + (∠D + ∠F + ∠B) = 360°
∠A + ∠B + ∠C + ∠D + ∠E + ∠F = 360°