Answer : The value of angle marked with 'x' is,

Step-by-step explanation :
The given figure is a kite in which two pairs of adjacent sides are equal.
According to the property of kite, one pair of opposite angles are equal (the angles are between unequal sides).
The angles between unequal sides are,
and

As we are given that:

Thus,

Therefore, the value of angle marked with 'x' is,
