caranya juga!....terimakasih

ΔADC = segitiga sama kaki
∠ADC = ∠ACD = (180° - 50°) x 1/2 = 65°

∠ADB = 180° - 65°
(4x + 15)° = 115°
4x° = 115° - 15°
x° = 100° x 1/4
x° = 25°

Semoga membantu^^
Jadikan terbaik ya, makasih

Diket
AD = AC

berarti
sudut ADC = sudut ACD
segitiga jml semua sudutnya 180°

ADC = 180-50-ACD
ADC = 180-50-ADC
2ADC = 180-50
2ADC = 130
ADC. = 65

Ditanya
ADB = ...?
ADB = 180-65
ADB = 115
4x + 15 = 115
4x. = 115-15
4x. = 100
x. = 25