A Comment "If i know the measures of angles C and B, I can find the measures of A and D" is TRUE
Explanation :
If we know angles C and B we can find angles A and D as,
As from figure we know
A+B = 180°
∴ A = 180° - B ... we know B so we get A
Also,
B+C+D = 180° ... as BCD is a triangle
∴ D = 180° - (B+C) ... we know B and C so we get D
