1/4x+105°+1/3x+40°=180°
7/12x=180°-145°
7/12x=35°
x=35°×12/7
x=60°
2)2x-55°=1/3x+45°
2x-1/3x=55+45
1 2/3x=100°
x=100°×3/5
3)1/3x+95°+2x-20°=180°
2 1/3x=180-75
7/3x=105°
x=105°×3/7
x=45°
4)x+45°=1/4x+105°
x-1/4x=105-45
3/4x=60°
x=60×4/3
x=80°
1/4x+105°+1/3x+40°=180°
7/12x=180°-145°
7/12x=35°
x=35°×12/7
x=60°
2)2x-55°=1/3x+45°
2x-1/3x=55+45
1 2/3x=100°
x=100°×3/5
x=60°
3)1/3x+95°+2x-20°=180°
2 1/3x=180-75
7/3x=105°
x=105°×3/7
x=45°
4)x+45°=1/4x+105°
x-1/4x=105-45
3/4x=60°
x=60×4/3
x=80°