tolong jawab pertanyaannya berikut dengan caranya

1/ → a+90°+65° = 180
a+ 155 = 180
a = 180-155
a = 25°
→ b+30+110=180
b + 140 =180
b =40°
→ c+50+60= 180
c+110= 180
c =180-110
c = 70°
→d+45+80= 180
d + 125 = 180
d = 180-125
d= 55°

3/ a. x°+6x°+2x°= 180°
9x = 180
x = 180:9
x = 20
b. 2x+3x+90= 180
5x+90= 180
5x = 180-90
5x = 90
x =90:5
x= 18
c. 2x+3x+4x= 180
9x =180
x = 180:9
x= 20
d. 2x+3x+x =180
6x =180
x = 180:6
x = 30

• Yang nomor 2 saya lupa cara.