tolong donk besok dikumpulkan

123.
115 + <abc = 180
<abc+<bac+<acb = 180°
<abc + 35 + 65 = 180°
<abc = 180° - 100°
<abc = 80°

124.
180 = cab + abc + acb
180 = 40+180-5x+180-(4x-5)
180 = 40+180-5x+180-4x+5
180 = 405 - 9x
9x = 225
x = 25
<acb= 180 - (4x-5)
= 180-(4(25)-5)
= 180-95
= 85°