Answer:
43°
Step-by-step explanation:
(x + 53)° + (x + 74)° + 73° = 180°
(x + 53 + x + 74)° = 180° - 73°
(2x + 127)° = 107°
2x + 127 = 107
2x = 107 - 127
2x = - 20
x = - 20/2
x = - 10
[tex]m\angle A = (x +53)\degree \\\\
m\angle A = (-10 +53)\degree \\\\
m\angle A = 43\degree \\\\
[/tex]
