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In triunghiul dreptunghic ABC,cu m(∡A)=90°,AB=24 cm.Daca tg B=0,75,calculati aria si perimetrul tringhiului.

Răspuns :

tg B=0.75=75/100=3/4.
tg B= cateta opusa/cateta alaturata=AC/AB⇒3/4=AC/AB⇒3/4=AC/24⇒AC= (3*24)/4⇒AC=3*6=18.
APLICAM PITAGORA
AB²+AC²=BC²⇒24²+18²=BC²⇒576+324=BC²⇒BC²=900⇒BC=30
Aria= produsul catetelor/2=(AC*AB)/2=(18*24)/2=18*12=216
Perimetrul=suma tuturor laturilor=AB+AC+BC=24+18+30=72
ΔABC dreptunghic ⇒ tg B= cateta opusa/cateta alaturata
0,75 = AC/AB⇒ 75/100 = AC/24⇒ 100AC=75*24
⇒ AC=75*24/100⇒ 3*24/4=3*6=18 cm⇒ AC =18cm

Aria Δdreptunghic= C1*C2/2= AB*AC/2= 18*24/2=9*24= 216 cm²

ΔABC dr⇒ TP⇒BC²= AB²+AC²⇒ BC²=576+324⇒BC²=900⇒ BC=√900⇒
BC=30cm

P ΔABC= AB+AC+BC= 18+24+30=72 cm