A.
because the total distance of every triangle 180. Add the two other angles so 42+ 57 =99. Then you have to subtract those two combined angles to find the missing one from the total distance, which is 180. 180-99=81. the answer is A. 81
EF = 50 in.
In similar figures, corresponding sides are proportional. We use the similarity statement ABCD~EFGH to write a proportion:

Cross multiply the proportion:
45*x = 75*30
45x = 2250
Divide both sides by 45:
45x/45 = 2250/45
x = 50
1/2 = 4/8
3/8 = 3/8
8 is the common denominator between these two fractions