Hey there!
First, we know that all the angles sum to 180 degrees (just like all the angles in a square sum up to 360).
Second, what we will need to do is subtract the first number from 180. (As shown below):
180 - 56 = 124
As you can see above, our answer is 124.
Third, we have this equation:
' 124 + y - 12 = 180 '
As mentioned in the beginning, we need to find what y equals.
Forth, we will solve the equation. (Shown below)
1 . Add 12 to both sides (cross out the double 12)
2. Bring down the 124 + y
3. Lastly, subtract 124 from 192. Your answer is 68.
124 + y - 12 = 180
↓↓ + 12 + 12
124 + y = 192
192 - 124 = 68
Your answer is choice A. 68.
Hope this helps!