Aflati aria triunghiului ABC echilateral cu A(-1,2) si B(0,5)

Răspuns :

AB=rad[(xB-xA)^2 + (yB-yA)^2]
AB=rad[(0+1)^2 + (5-2)^2]
AB=rad(1+9)
AB=rad10
Aria=L^2rad3/4
Aria=10rad3/4
Aria=5rad3/2
AB²=1²+3²=1+9=10
aria=AB²√3/4=10√3/4=(5√3)/2 unitati patrate