Geometry Practice Test 4

Draw a perpendicular AD on
∠BAD = 40°
∠ADB = 90°
In ΔABD,
∠BAD+∠ADB+∠DBA = 180°
180° − (40° + 90°) = ∠DBA
∠DBA = 50°
And ∠OBD = 25°
In ΔBOC,
∠OBC+∠OCB+∠BOC = 180°
∠BOC = 180° − (25° + 25°)
∠BOC = 130°