Jawabanmu

2014-05-05T16:25:29+07:00
13x+3+7x-3=180 20x=180 x=9 7(9)-3 63-3=60
2014-05-05T16:27:14+07:00
13x + 3 +7x -3 =180 <=> 20x = 180 <=> x = 180/20 = 9 <=>besar sudut boc = 7x9-3 = 60 
<=> maka, besar sudut penyiku = 90-60 = 30 derajat