Question

Dau coroana pls repede +25 pct !!!!

Answer 1

Răspuns:

ΔABC isoscel

AB=AC , AB=15cm, BC=24cm

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$h_{A} ,h_{B} ,h_{C} =?$

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In ΔABC isoscel construim $h_{A}$⊥ BC, $h_{A}$∩BC={D} ⇒ ΔADC si ΔADB dreptunghice , D mij lat BC ⇒BD=CD=12cm

In ΔADB dreptunghic, m∡ADB=90°, conform teoremei lui Pitagora ⇒

⇒AB²=AD²+BD² ⇒ AD²=AB²-BD²

AD²=15²-12²=225-144=81

AD=√81= 9cm

$A_{ABC} =\frac{B*h}{2}= \frac{BC*AD}{2}=\frac{24*9}{2}=12*9= 108cm^{2}$

$A_{ABC}=\frac{AC*h_{B} }{2} =\frac{AB*h_{C} }{2}$

$108=\frac{15*h_{B} }{2} \\216=15*h_{B}\\ h_{B}=\frac{216}{15}=14,4cm$

Cum ΔABC este isoscel ⇒$h_{B} =h_{C}=14,4 cm$