Answer:
Therefore the value of x is 3.5 unit.
Explanation:
Given:
AC = 5
BC = 6
DB = 4.2
∠ACD = ∠BCD
To Find:
AD = x = ?
Solution:
∠ACD = ∠BCD ........Given
i.e CD is the angle Bisector of ∠ ACB
Angle Bisector Theorem:
An angle bisector of an angle of a triangle divides the opposite side in two segments that are proportional to the other two sides of the triangle.
i.e
....Angle Bisector Theorem
Substituting the values we get

Therefore the value of x is 3.5 unit.