You are comparing side AB, angle ABD, and side BD in one triangle to side CB, angle CBD, and side BD in the other triangle. That is, you are comparing a Side, Angle, and Side in each triangle. The SAS postulate is the reason the triangles are congruent.
Answer:
x=4
Step-by-step explanation:
5x+10=30
Subtract 10 from each side
5x=20
Divided each side by 5
x=4
You didn'tlist any but anyway

so

so the possible expressions could be

and/or
Answer:
Um, where is the problem?
Step-by-step explanation:
There are 100 years in a century