Tolong kasih tau caranya ya

ΔBCD=ΔCAD
BD/CD=CD/AD
BD=(CDXCD)/AD
BD=(6X6)/4=9cm

CB=√CD^2+BD^2=√36+81=√117=3√13 cm

CA=√CD^2+AD^2=√36+16=√52=2√13 cm

L ADC=(ADXCD)/2=4X6/2=12 cm
L BCD=(CDXBD)/2=6X9/2=27 cm
L ABC=(ACXBC)/2=(2√13X 3√13) /2=39 cm

diperiksa lagi yaa......