PLease help me! I hope it's not difficult... Please help me in this

Which triangle congruence postulate or theorem justifies my claim that the steps i made using construction paper and scissors produce an isosceles triangle? was it sss, sas, asa, aas, or hl?

2y= 3 2 x−2 y = − 1 3 x + 1 y=− 3 1 x+1

If chord ab is congruent to chord cd, then what must be true about ef and eg?