besar

Mapel : Matematika
Bab : Sudut

Diketahui :
- ∠BAC = (3x + 5)°
- ∠ACB = 2x°
- ∠CBD = 105°

Ditanya :
- ∠BAC = .....?

Penyelesaian :
- ∠ABC :
∠ABC = 180° - ∠CBD
∠ABC = 180° - 105°
∠ABC = 75°

- ∠BAC :
∠BAC + ∠ACB + ∠ABC = 180°
(3x + 5)° + 2x° + 75° = 180°
3x° + 5° + 2x° + 75° = 180°
3x° + 2x° + 5° + 75° = 180°
5x° + 80° = 180°
5x° = 180° - 80°
5x° = 100°
x = 100°/5°
x = 20°

∠BAC = (3x + 5)°
∠BAC = (3(20) + 5)°
∠BAC = (60 + 5)°
∠BAC = 65°

Jawaban : C. 65°

Maaf Kalau Salah