Jawapan: x = 40 Penjelasan: => 1/2 (180 - x) + (90 - x) = 120 => 180/2 - x / 2 + 90 - x = 120 => 90 - x / 2 + 90 - x = 120 => 90 + 90 - x - x / 2 = 120 => 180 - (3x) / 2 = 120 => (3x) / 2 = 180 - 120 => (3x) / 2 = 60 => x = 2/3 × 60 => 40
