Tolong Dijawab Nomor 3 sampai 5 Pake Cara Kerja #Terimakasih Yg Mau Jawab

2.sudut berpelurus = 180°
 pelurus dari ;
   a.69° =180-69 =111°
   b.117°=180-117=63°
  c.79,2° =180-79,2 =100,8°
 d.152,4° =180-152,4 =27,6°

3.∠a =180-138 =42°
  ∠b=180-42 =138°
  ∠c=180-138=42°
  ∠ bertolak belakang sama besar

4.a.5x-10+ 7x-20 = 90°
       5x+7x-10-20=90
           12x -30 =90
                  12x =90+30
                      x =120/12

    b.∠AOB =5x-10 =5(10)-10 = 40°
   c.∠COB =7x-20 =7(10)-20 =50°

5.∠ AOB =90°
  ∠ BOC =90°