Answer: Missing parts are,
In first blank, [tex]AD\cong DC[/tex],
In second blank, SAS postulate
In third blank, CPCTC postulate
Step-by-step explanation:
Since, Here D is the mid point on the line segment AC.
And BD is a perpendicular to the line AC.
Therefore, In triangles ADB and CDB ( shown in figure)
AD\cong DC ( By the definition of mid point)
[tex]\angle BDA\cong \angle BDC[/tex] ( right angles )
[tex]BD\cong BD[/tex] ( reflexive)
Thus, By SAS ( side angle side )postulate,
[tex]\triangle ADB\cong \triangle CDB[/tex]
So, by CPCTC( Corresponding parts of congruent triangles are congruent)
[tex]AB\cong CB[/tex]
Now, By definition of congruent segment,
AB=CB
By definition of equidistant,
B is equally far from both A and C.