ducem CM inaltime perpendiculara pe AB
A=AB×CM/2
40√3=16×CM/2
CM=80√3/16=5√3
daca m(<A)=60° ⇒ sin 60°=√3/2 CM/AC=5√3/AC=√3/2 AC=10
AM=√[10²-(5√3)²]=√(100-75)=√25=5
MB=16-5=11
BC=√[11²+(5√3)²]=√(121+75)=√196=14
A=BC×AD/2
40√3=14×AD/2
AD=80√3/14=(40√3)/7 =5,(714285)√3