K think that the answer is 3
Answer:
1) 
2) 





Step-by-step explanation:
The Pythagorean Theorem is:

Where a is the hypotenuse and b and c are the legs.
The missing side lenght is one of the legs, then you must solve for one of them. Therefore, this is:

MEASURE OF ANGLE:
Keep the identities on mind:



Susbstitute values, then:






B) 40, knowing that DCA is 155 is helpful because then you can figure out angle C. 180-155 is equal to 25. Then, 115+25= 140. 180-140= 40