In the isosceles triangle ABC, if angle a = 36 degrees, ab = AC, and the bisector BD of angle B intersects AC at point D, then CD: ad =?

In the isosceles triangle ABC, if angle a = 36 degrees, ab = AC, and the bisector BD of angle B intersects AC at point D, then CD: ad =?

=sin36：sin72
=1：2cos36

In △ ABC, ab = AC, ∠ a = 36 ° BC = 6, then the bisector BD=______ ．

In ∵ △ ABC, ab = AC, ∵ a = 36 °∵ ABC = ∵ C = 72 °∵ BD is the angular bisector ∵ abd = ∵ DBC = 12 ∵ ABC = 36 °∵ C = ∵ CDB = 72 °∵ BC = BD = 6

In △ ABC, ab = AC = 10, ∠ a = 36 °, BD is the angle bisector intersecting AC at D, then DC=______ ．

And the \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\∵ CD < AC, AC = 10, ∵ X1 = 15 + 55 So the answer is: 15-55