Jawabanmu

2014-01-16T17:42:59+07:00
180 = 90+4x+7+8x-1
84=12x 
x =7
sudut a = 35 
sudut c = 55 
1 5 1
2014-01-16T17:53:17+07:00
(4x + 7) +90 +(8x-1) = 180
(4x+7)+ (8x-1) +90= 180
12x +6+90= 180
12x = 180-96
x= 84/12
 = 7

sudut A = 4x + 7 = (4 . 7 ) +7=35 derajat
sudut c = 8x-1=(8 . 7)-1= 55 derajat