Răspuns:
Explicație pas cu pas:
7)
10x-15 +3x=180
10x+3x=180+15
13x=195
x= 195:13
x= 15 °
-
8)
∡ABD= 60+50
∡ABD= 110 °( unghi exterior triunghiului )
-
9)
ΔBDC= 90°
- ∡DBC= 40 °
↓
∡C= 180- 90-40
∡C= 50°
-
Δ ABD- ∡ADB= 90 °
- ∡ABD= 25 °
↓
∡A= 180- 90-25
∡A= 65°
-
∡A- ∡C= 65-50=15 ° (diferenta )
-
10)
∡A+∡B=180°-∡C
∡BAI = ∡A/2
∡ABI= ∡B/2
∡BAI + ∡ABI= ∡A/2+∡B/2=(∡A+∡B)/2= 14/2=70°
∡AIB= 180- ∡BAI +∡ABI =180- 70=110°
↓
∡AIB= 110 °
