Answer:
Choice C is correct answer.
Step-by-step explanation:
From question statement, we observe that first interior angle = 56°
second interior angle = y-12°
and
third interior angle = y°
We have to find the value of y°.
Since,we know that sum of all interior angle is 180°.
Hence,we can write
56°+y°+(y-12)° = 180°
hence,
2y°+44° = 180°
Adding -44° to both sides of above equation,we get
2y°+44°-44° = 180°-44°
2y°+0= 136°
Dividing by 2 to both sides of above equation,we get
2y°/2 = 136°/2
y° = 68° which is the answer.