Draw line AB = 1cm, extend AB to point C, make BC = Zab, and then extend Ba to point D, make ad = 3AB, then DC=____ cm,DA=____ cm.

Draw line AB = 1cm, extend AB to point C, make BC = Zab, and then extend Ba to point D, make ad = 3AB, then DC=____ cm,DA=____ cm.

Is BC = 2Ab? If so, because ad = 3AB, so ad = 1 / 3cm, and because BC = 2Ab, so BC = 2, so CD = Da + AB + BC = 1 / 3 + 1 + 2 = 10 / 3cm