PLEASE HELP!
I NEED BOTH PARTS!

a) Yes agree

and b) (I'm not too sure about this one but I think..) By CPCT that is Corresponding parts of congruent triangles are equal/congruent theorem.

Step-by-step explanation:

I'll use this " [ " symbol for angle.

a) yes agreed ;

AB = CB (B is the midpoint of AC)

[ ABD = [ CBD = 90°

BD = BD (common side)

--> therefore by SAS criteria triangle ABD is congruent to triangle CBD.

and by CPCT AD = CD .

b) AD = CD (proven by CPCT)

...answer for b you're likely suppose to write it that way. so yeah hope this helps.