bonjour

albums belges = x

albums français  = 2 x

x + 2 x + 25 = 148

3 x = 148 - 25

3 x = 123

x = 41

41 belges ,  82 français et  25 autres  

angle BCA = x

angle BAC = 3 x

x + 3 x + 90 = 180

4 x = 180 - 90

4 x = 90

x = 22.5

BCA = 22.5 °

CAC = 67.5 °

ABC = 90 °