In the given figure ABCD is a rhombus, the value of $x$ is.

50°

Note:

1. In a rhombus diagonals are intersect at right angle.

2. All sides are equal and opposite sides are parallel.

Now, In the rhombus:

\(\angle\)OAB = 40°

\(\angle\)AOB = 90°

\(\angle\)CDB = \(\angle\)DBA = x°          (alternate interior angles)

In ΔAOB:

⇒ Sum of all three angles = 180°

⇒ 40° + 90° + x° = 180°

⇒ x = 50°