Answer:
a = 112°
Step-by-step explanation:
Use triangle ABP:
m<P + m<PAB + m<PBA = 180°
m<PAB = m<PBA = x
m<P + 2x = 180°
68° + 2x = 180°
2x = 112°
x = 56°
m<PAB = m<PBA = 56°
Use triangle ABO:
m<O + m<OAB + m<OBA = 180°
m<O = a
m<OAB = m<OBA
m<OBA + m<PBA = 90°
m<OBA + 56° = 90°
m<OBA = 34°
m<OAB = m<OBA = 34°
a + 34° + 34° = 180°
a = 112°
