Tolong jawab yak:) pakai cara yak;)

3a+2a+a= 90
6a=90
a=90/6
=15

2).
nilai a
90 = 3a + +2a + a
90 = 6a
90/6 = a
15° =a

AOB
= 3a
= 3(15)
=45°
BOC
=2a
=2(15)
=30°
COD
=a
=15°

3). sudur x
180 = 30 + 35 + x + 35
180 = 100+ x
180-100 =x
80° = x


DOB
=x + 35
=80 +35
=115°