Solution: According to the fact that the outer angle of a triangle is equal to the sum of two angles that are not adjacent to it:

∠ACD=∠A+∠ABC

∠A`CD=∠A`+∠A`BC

Available:

∠A=∠ACD-∠ABC

∠A`=∠A`CD-∠A`BC

=∠ACD/2-∠ABC/2

=(∠ACD-∠ABC)/2

=∠A/2

=35

The quantitative relationship between ∠A and ∠ A' is as follows:

∠A=2∠A '