Be with this i'll give you lots of pints

Find the value of the cosine for angle a

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?

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer