Răspuns :
1)
apotema VM cu pitagora VM=√(VA^2-AM^2)=√(26^2 - 100)
VM=24 mm
CM=AC√3/2 = 10√3 mm
MO=CM/3=10√3/3 mm
inaltimea VO, pitagora ⇒ VO=√(VM^2 - MO^2)=√(24^2 - 300/9)
VO=2√1221 / 3 mm
2)
AB⊥CM
AB⊥VM ⇒ AB⊥(VMC) ⇒ AB⊥VC
3)
am aratat ca AB⊥(VMC) rezulta ca AB⊥MN
aria NAB este minima daca inaltimea NM este minima adica MN⊥VC
aria VMC in 2 moduri ⇒ VC x MN=MC x VO
MN=10√407/13 mm
aria minima NAB=AB x MN/2=20 x 10√407/26=100√407/13
cu pitagora in VMN ⇒ VN=√(VM^2 - MN^2)=238/13 mm
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