Set of real numbers satisfying 2x=3

I'm being volume of cylinder with 13 in. radius and 30 in height answer choices in pic

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?

Write 17/20 as a decimal and as a percent.