I forgot what a multiple is. Can someone please tell me.

a number that can be divided by another number without a remainder.

A multiple is a number that basically can be a number that can be divided by another number without a remainder.

if you explain the the question more correctly i might be able to answer this better

step-by-step explanation:

δabc ≅ δdcb by sas because

db ≅ ac . . given (side)

bc ≅ bc . . reflexive property (side)

∠dbc ≅ ∠ acb . . alternate interior angles where transversal bc crosses parallel lines bd and ac (included angle)