Step-by-step explanation:
<1 = 180°-102° = 78° (the extended angle is 180°)
<2 = <5 = 58°
<3 = 180° - 78° - 58° = 44° (the sum of the angles inside of a triangle is 180°)
<4 = 180° - 44° - 58° = 78° = <1 (the extended angle is 180°)
