Respuesta :

m∠ADB + m∠BDC = m∠ADC  
x + x + 10 = 60 
2x + 10 = 60
2x = 60 - 10
2x = 50
x = 50/2
x = 25

a
m
∠ADB = x = 25°


m∠BDC = x + 10 = 25 + 10 = 35°

с
 Angle Addition Postulate