Answer with Step-by-step explanation:
We are given that A, B and C are subsets of universal set U.
We have to prove that

Proof:
Let x
Then
and 
When
then
but 
Therefore,
but 
Hence, it is true.
Conversely , Let
but 
Then
and
When
then 
Therefor,
Hence, the statement is true.
Answer:
A
Step-by-step explanation:
The triangles are the same size but in a different form. Y= 50 and a and b equal eachother.
Answer:
D ASA
Step-by-step explanation:
ASA
It would be ten because 40 divided by 4 is ten