Tolong dibantu nomor 1 dan 2, pakai cara yah. Trims.

1. sudut ABC = 180° - 65°-70°
= 45°
sudut CBD = 180° - sudut ABC
= 180°- 45°
= 135°
2. A° = 180°-60°
= 120°
B° = 180°-40°
= 140°
C° = 180° - 80°
= 100°
a+b+c = 120° + 140° + 100°
= 360°

maaf kalau salah