In the figure, O is the centre of a circle passing through points A, B, C and D and ADC = 120
Find the value of x.

30 degrees

Step-by-step explanation:

The computation of the value of x is given below:

Given that

ADC = 120 degrees

So ABC = 60 degrees

As the sum of the opposite angles are 180 degrees

And ACB = 90 degrees

Now in Triangle ADC

Angle ACB + Angle ABC + x = 180 degrees

90 + 60 + x = 180

x = 30 degrees