Question

heiii va rog frumos sa ma ajutati cu problema asta​

Answer 1

Răspuns:

suma ∡ Δ=1`80 ; x+y+z=180 ;  x/5=Y/3=Z/4=K ,  X=5K ;Y=3K ;Z=4K;  5K+3K+4K=180 ;  12K=180 ; K=180/12=15;

Explicație pas cu pas:X=5×15=75 ;  Y=3×15=45 ;   Z =4×15=60 ;    b)                  ∡CAD=30°   ;   DC/AC=1/2 ;   ΔAGB isoscel ;   DB=AD ; DB/2AD=1/2

Answer 2

{∡A,∡B,∡C} d.p.{5,3,4}

∡A/5=∡B/3=∡C/4=k

∡A/5=k=>∡A=5k

∡B/3=k=>∡B=3k

∡C/4=k=>∡C=4k

∡A+∡B+∡C=180°<=>5k+3k+4k=180°<=>12k=180°=>k=180°/12=15°

∡A=5k=5*15°=75°

∡B=3k=3*15°=45°

∡C=4k=4*15°=60°

In ΔADB , m(∡D)=90°=>ctgB=BD/AD=>BD/AD=1

In ΔADB , m(∡D)=90°=>cosC=DC/AC=>DC/AC=1/2

BD/AD=1 |*(1/2)=>BD/2AD=1/2

1/2=1/2=>BD/2AD=DC/AC