NOMOR 12 & 13 tiling dijawab

12.
3x + 2x - 10 = 180
5x = 180 + 10
x = 190 : 5
x = 38°
<BDC = 2x - 10
= 2(38) - 10
= 76 - 10
= 66° (B)

#12
180 = 3x + (2x - 10)
180 = 3x + 2x - 10
180 + 10 = 3x + 2x
190 = 5x
x = 190/5
x = 38

Sudut BDC = 2x - 10 = 38*2 - 10 = 66

Jawaban: B. 66

#13
y = 50 + (180 - 115)
y = 50 + 65
y = 115

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