tolong bantu jawab yg di lingkarin soqlnya harus di kumpulkan besok

26) ∠abc + ∠cbd = 180
       2a + 4 + 3a + 6 = 180
       5a + 10 = 180
       5a = 170
       a = 34

∠cbd = 3a + 6
         = (3×34) + 6
         = 102 + 6
         = 108

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28) 1/jhon+Dery = 1/Jhon + 1/Dery
                           = 1/60 + 1/30
                           = 1+2/60
                           = 3/60

Jhon + Dery = 60/3
                    = 20

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29) 6.000.000 + (6.000.000 × 5/100) =
      6.000.000 + 300.000 = 6.300.000

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30) a+r+c = 180
      25+60+c = 180
      85+c = 180
      c = 180-85
      c = 95

c+d = 180
95+d = 180
d = 180-95
d = 85

p+a+b = 180
p+25+p = 180                             (karena p=b)
2p+25 = 180
2p = 180-25
2p = 155
p = 77,5

semoga membantu :)