a)
gamma = 180° - alpha - beta = 31°
b = a·sin(beta)/sin(alpha) = 4,835
c = sqrt(a² + b² - 2·a·b·cos(gamma)) = 4,341
b)
c = sqrt(a² + b² - 2·a·b·cos(gamma)) = 11,723
alpha = acos((b² + c² - a²)/(2·b·c)) = 42,81°
beta = 180° - alpha - gamma = 17,19°
c)
alpha = acos((b² + c² - a²)/(2·b·c)) = 44,16°
beta = acos((a² + c² - b²)/(2·a·c)) = 39,58°
gamma = 180° - alpha - beta = 96,25°