Question

Va roggggg
Dau coroanaaaaa
Urgenttttt
Plssss
Subiectul 3 cu toate punctele (1,2,3,4)

Answer 1

Răspuns:

1.∡AOB+∡BOC+∡COA=360°

∡AOB=∡BOC+30°

∡AOB=∡COA-30°

∡BOC+30°=∡COA-30°=>∡COA=∡BOC+60°

(∡BOC+30)+∡BOC+(∡BOC+60)=360°

∡BOC·3+90=360°

∡BOC·3=270=>∡BOC=270:3=>∡BOC=90°→ unghi drept

∡AOB=120°

∡COA=∡BOC+60=90+60=>∡COA=150°

raspuns b

2.∡AOC=∡AOB+∡BOC=20°+70°=90°

raspuns c

3. 90°-∡AOB=(180°-∡AOB)/3

3(90-∡AOB)=180-∡AOB

270°-∡AOB·3=180°-∡AOB

270°-180°=∡AOB·3-∡AOB

90°=∡AOB·2

∡AOB=90°:2

∡AOB=45°

raspuns c

4. suma unghiurilor intr-un punct =360°

2+4+6+...+2n ≤ 360° fara ∡ nul

suma lui Gauss

2·(1+2+3+...+n) ≤ 360°

2·[n·(1+n)]/2 ≤ 360

n·(n+1) ≤ 360

dam valoarea lui n cea mai mare

n=18

18·(18+1) ≤ 360

342 < 360 =>nr maxim de unghiuri =18

raspuns d