Ta có: `AOC-BOC=90^0`
`=>AOC=90^0+BOC`
Lại có: `AOC+AOC+BOC=180^0` (kề bù).
Và: `90^0+BOC+BOC=180^0`
`=>2BOC=90^0`
`=>BOC=45^0`
`=>AOC=90^0+45^0=135^0`
Ta có: `2AOC=3BOC`
`=>AOC=2/3BOC`
Lại có: `AOC+BOC=180^0` (kề bù).
`=>3/2BOC+BOC=180^0`
`=>5/2BOC=180^0`
`=>BOC=(2*180^0)/5=72^0`
`=>AOC=3/2*72=108^0`