z = x (alternate angles)
w = y (alternate angles)
w + 75° =180° |-75°
w = 105° → y = 105°
z + w + 30° = 180°
(the sum of measures of the angles in a triangle is equal 180°)
z + 105° + 30° = 180°
z + 135° = 180° |-135°
z = 45° → x = 45°
