tg ( ∡ AD ; EC ) = tg ( ∡ EH ; EC )
EC diagonala in cub
EC = l√3= 6√3
ΔCEH
HC diagonala in patrat
HC = l√2 = 6√2
( 6√3 ) ² = 36 × 3 = 108
( 6√2 ) ² =36 × 2 = 72
6² =36
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( 6√2 ) ² + 6² = ( 6√3 ) ² => din reciproca teoremei lui Pitagora ca ΔCEH - dr in H
tg ( ∡ EH ; EC ) = tg ( ∡ HEC ) = HC / EC = 6√2 / 6√3 = √2 / √3 = √6 / 3