Respuesta:
a = 10/3
Explicación paso a paso:
SCa + SSCCa + SSSCCC3a + SSSSCCCC4a =200°
S(90° - a) + a + SC(3a) + 4a = 200°
[180° - (90° - a)] + 5a + S(90° - 3a) = 200°
(90° + a) + 5a + [180° - (90° - 3a)] = 200°
90° + 6a + (90° + 3a) = 200°
180° + 6a = 200°
6a = 20°
a = 10/3