Răspuns:
Explicație pas cu pas:
EF || GH
AE = EG = GB => AE = AB/3 => EF = BC/3
Aria Δ ABC = 27 cm²
Aria Δ ABC = BC · AM / 2 ;
AM ⊥ BC ; AN ⊥ GH ; AP ⊥ EF
Aria Δ AEF = (EF·AP)/2
AP = AM/3 => Aria Δ AEF = (BC/3 ·AM/3)/2 =
= Aria Δ ABC /9 = 27/9 => Aria Δ AEF = 3 cm²
GH = 2BC/3 ; NP = AM/3
Aria EFGH= (GH+EF)·NP/2 = [(2BC/3 + BC/3)· AM/3]/2 =
= BC·AM/6 = 27/3 = 9 cm²
=> Aria EFGH = 9 cm²
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