Answer: The answer is (C) 180°.
Step-by-step explanation: Given that m∠A = 40°. ∠B is a complement of ∠A and ∠C is a supplement of ∠B. We are to find m∠B + m∠C.
Since ∠B is a complement of ∠A, so we have

Now, since ∠C is a supplement of ∠B, so we have

Therefore,

Thus, (C) is the correct answer.
Could not do the 2nd one, but will update if I figure it out
Answer:
EF = ~3.8
Step-by-step explanation:
Apply the sine theorem:
EF/sinD = DE/sinF
=> EF = DE*(sinD/sinF)
= 3*(sin75/sin50)
=3.78 = ~3.8
Hope this helps!
It would actually be 62.5