Answer:
a = 105°
Step-by-step explanation:
Use the supplements of the angles near A and B.
180 - 140 = 40
The interior angle near A measures 40°.
180 - 145 = 35
The interior angle near B measures 35°
Now use the sum of the measures of the angles of a triangle:
The sum of the measures of the interior angles of a triangle is 180°
a + 40 + 35 = 180
a + 75 = 180
a = 105
