Answer:
first one: 53°
Second one: reflective property of congruence <-(I'm not sure on this one but it seems like it)
Explanation:
First one:
The measure of every triangle is 180°
we have to find that missing angle
so 180-53-74=53°
If its harder to understand you can make angle E x and solve 180=x+53+74
For the second one:
The reflexive property of congruence states that any geometric figure is congruent to itself.
This means that even same line segments and be congruent because of this property.
I hope this helped