Given:
There are given that the triangle with an interior angle.
Where,
The interior angles are :

Step-by-step explanation:
To find the value of the addition of x, y, and z, first, we need to draw the reimage.
Then,
The new image is:
Now,
First, we need to find the value of the angle of c.
Then,
From the formula to find the angle c:

Then,
Put the value of a and b into the above formula:
Then,
![\begin{gathered} \operatorname{\angle}a+\operatorname{\angle}b+\operatorname{\angle}c=180^{\operatorname{\circ}} \\ 72^(\circ)+57^(\circ)+\operatorname{\angle}c=180^{\operatorname{\circ}} \\ 129^(\circ)+\angle c=180^(\circ) \\ \angle c=180^(\circ)-129^(\circ) \\ \angle c=51^(\circ) \end{gathered}]()
Now,
Find all exterior angles x, y, and z.
Then,
First, find the value for x:

Then,
For the values of y:

And,
For the value of z:
Then,

Now,
Add the values of x, y and x:
Then,

Final answer:
Hence, the correct option is D.