Hi!
I have included an image that will help you understand.
So, a straight line has an angle of 180°. (look at the red angle in the image) Which means that we can subtract the 130° angle from 180°.
180 - 130 = 50
Now we know that the top angle in the triangle = 50°
We also know that the other two angles in the triangle are equal to each other.
So we can subtract 50° from 180°, then divide that by 2 to find the value of y.
180 - 50 = 130
130/2 = 65
The answer is D. 65°
Hope this helps! :)
-Peredhel