tolong bantu.y mtk .tunjukan nilai a

1). 90° = 2a + 3a
90°= 5a
90°/5 = a
18° = a

2). 180° = 46° + a+ 29° +5a+15°
180° = 90° + 6a
180°-90° = 6a
90° =6a
90°/6 =a
15° = a