S(ABC)/S(ACD) =AB/AD =9/8
ABC~ACD => S(ABC)/S(ACD) =k^2 => k=√(9/8)
AC=AD*k
CD^2 =AC^2 +AD^2 -2AC*AD*cosA =AD^2 (k^2 +1 -2kcosA)
AD^2 =40/(9/8 +1 -3/2) =64
AD=8; AC=6√2
S(ACD) =1/2 AC*AD*sinA =24
S(BCD) =1/8 S(ACD) =3
S(ABC)/S(ACD) =AB/AD =9/8
ABC~ACD => S(ABC)/S(ACD) =k^2 => k=√(9/8)
AC=AD*k
CD^2 =AC^2 +AD^2 -2AC*AD*cosA =AD^2 (k^2 +1 -2kcosA)
AD^2 =40/(9/8 +1 -3/2) =64
AD=8; AC=6√2
S(ACD) =1/2 AC*AD*sinA =24
S(BCD) =1/8 S(ACD) =3