a)VA+VB (piram regulata) =4√2
AB=8=4*2=4√2*√2⇒VAB tr .dr. isoscel⇒m∡(VA,VB)=90°
Altfel
(4√2)²+(4√2)²=8²⇒Rec. Teo, Pitagora Δ VAB dreptunghic in V, mas (VA,VB)=90°, cerinta
b)mas ∡(VA , BC)=mas ∡(VA, AD) dar ΔVAD≡ΔVAB 9fete latereale congruente)⇒mas ∡(VA, AD)=45°, cerinta
c)mas ∡(VD, AB)=mas∡(VD,DC)=45°, cerinta