.16 .AB = 1 BO = OC . = .6 ,4 ,3 ,2 12 1 – .17 .11 ,2 22 2 – .18 18 3 – .9 ,6 ,3 ,2 16 4 – 8 ,4 ,2 2 + 2 = 2 /√ √ 2+ 2= × 2 =2 × AD × 2 + 2 /∙ 2 2 =2 = AD × √ 2 + 2 /: √ 2 + 2 = + 6