besar sudut AOC adalah

4x+6+7x-4 = 90
11x+2 = 90
11x = 90-2
x = 88/11
x = 8,,,jadi sudut AOC 4×8+6 = 38

90° = 4x + 6 + 7x - 4
90° = 4x + 7x + 6 - 4
90° = 11 x + 2
90° - 2 = 11 x
88° = 11x
88/11 = x
8 = x

sudut DOA = 90°
sudut AOC = sudut DOA + sudut DOC
= 90° + 4x + 6
= 90° + 4(8) + 6
= 90° + 32 + 6
= 90° + 38
= 128°