Question

Identify which triangles are congruent, and explain your answer.

Answer 1

I believe that A and D would be the correct answer. Because both are 30,60,90 triangles and would be congruent. The other 2 triangles only have 1 angle and their side measures are at two different places meaning they cannot be congruent.

Answer 2

This is a 30-60-90 triangle. Following the pattern of x, $x \sqrt{3}$, and 2x. So lets us look for that pattern in these triagles.
Judging from what I know, the answer is A and C. 
They hypotenuse is 2 times the shorter leg, which is evident here. B and D are incorrect, since if the longer leg is 18, then the smaller leg would be a large square root , possibly a number in the mid 500s being squared.
Hope this helps