Răspuns:
Explicație pas cu pas:
cos20 si sin20 se pot afla numai cu calculatorul
cos20 ~ 0,94, sin20 ~ 0,34
a)<BAD = <ACD = 20
cos(BAD) =cos20 = AD/AB = AD/5
AD = cos20*5 ~ 0,94*5
b) sin(ACD) = sin20 = AD/AC = cos20*5/AC
AC = cos20*5/sin20 ~ 0,94*4/0,34
c) sin(BAD) =sin20 = BD/AB =BD/5
BD = sin20*5 ~ 0,34*5
cos(ACD) = cos20 = CD/AC = CD/(cos20*5/sin20 )
CD = cos20*(cos20*5/sin20 )
BC = BD+CD = sin20*5 + cos20*(cos20*5/sin20 )
Aria = BC*AD/2 = etc.
O mizerie de problema !
