In the figure, if ∠A + ∠B + ∠C + ∠D + ∠E + ∠F = k$\times {90}^o$, then find the value of k.

 In △ABC,

⇒  ∠A + ∠B + ∠C =180$°$ ... [Sum of interior angles of a triangle is 180^∘] ------- ( 1 )

 In △DEF,

⇒  ∠D + ∠E + ∠F = 180$°$...  [Sum of interior angles of a triangle is 180^∘] -------( 2 )

⇒  ∠A + ∠B + ∠C + ∠D + ∠E + ∠F = 180$°$ + 180$°$

 Adding ( 1 ) and ( 2 ), we get:

⇒  ∠A + ∠B + ∠C + ∠D + ∠E + ∠F = 360$°$

⇒  ∠A + ∠B + ∠C + ∠D + ∠E + ∠F = 4 × (90^o)

By comparing the given equation, we get:

k = 4

Therefore, 4 is the correct asnwer.