tolong bantu jawab no 3 besok dikumpulkan

L ADC + L ABC = 180
(3x + 20) + (4x - 15) = 180
3x + 20 + 4x - 15 = 180
7x + 5 = 180
7x = 180 - 5
7x = 175
x = 175/7
x = 25°
L ADC = 3x + 20
= 3.25 + 20
= 75 + 20
= 95°
L ABC = 4x - 15
= 4.25 - 15
= 100 - 15
= 85°