Respuesta :

hola1104
straight line = 180 degrees so angle opposite a = 180-128 = 52
then triangle adds up to 180 degrees so a= 180-52-73 =55 degrees

Answer:

Take the angle above 128° as x.

x = 180 - 128 (linear pair)

x = 52°

a = ?

a = 180 - ( 52 + 73 ) ( the angles in a triangle add up to 180° )

a = 180 - 125

a = 55°