Answer:
50°
Step-by-step explanation:
ABCD is a kite.
Therefore, AB = BC
[tex]\therefore m\angle BCA= m\angle BAC = 40\degree \\
\because BD \perp AC.. (Diagonals \: of\: kite) \\
\therefore y + 90\degree + m\angle BCA = 180\degree \\
\therefore y + 90\degree + 40\degree = 180\degree \\
\therefore y = 180\degree - 130\degree \\
\huge\red {\boxed {y = 50\degree}} [/tex]
