daca M e mijlocul laturii BC=> AM mediana si mediana imparte triunghiul in 2 triunghiuri de arii egale, adica ABM are aria de ABC/2=36/2=18.
Aria ABC= AB * BC * sin ( ABC ) = 36
Aria ABM= AB * BM * sin ( ABM ) = x
<ABM = < ABC => sin ( ABC ) = sin ( ABM ) = sin 90 = 1
Aria ABC = AB*BC=36
Aria ABM = AB*BM=x
Aria ABC / Aria ABM= AB*BC/AB*BM= 36/x
AB*BC/AB*BM=36/x
BC/BM=36/x
M mijloc BC => BM = BC/2
BC/BM = BC/BC/2 = 2
2=36/x=> 2x=36 => x = 36/2 =18 cm ²
( Am impresia ca m-am complicat, dar in orice caz sper ca te-am ajutat )
