Apply $45-45-90$ degree triangle sides formula to find the other sides of a triangle whose one side is $8\sqrt{2} \mathrm{cm}$

A triangle has _____ vertices. (one/two/three/four)

The exterior angle of a triangle is equal to the sum of the _____ angles opposite to it.

In a$ABC$, if $\angle A=\angle C,$ then $AB=$_____.

The sum of three angles of a triangle is equal to _____$°$ .