Question

ΔABC DREPTUNGHIC
m(unghiuluiA)-90°
AD  perpendicular cu BC
DC egal cu 4cm
AD:?
aflati aria ABC
BDegal 40cm

Answer 1

Daca BD = 40 cm si DC = 4 cm, folosesti T. inaltimii si afli pe AD = 4$\sqrt{10}$
cm;
ai ca BC = 44 cm; aria(ABC) = (AD*BC)/2 = 88$\sqrt{10} cm^{2} ;$
Bafta!

Answer 2

Cu teorema inaltimii⇒AD²=BD·DC=4·40=160⇒AD=4√10 cm
BC=BD+DC=44 cm
$A_{ABC}=\dfrac{BC\cdot AD}{2}=\dfrac{44\cdot 4\sqrt{10}}{2}=88\sqrt{10}\ cm^2$