All of the answer choices except B would be correct for this problem.
Answer:
The length of fencing will be 
Step-by-step explanation:
Step 1
Find the dimensions of the rectangle
we know that
The area of a rectangle is equal to

In this problem we have

so
-----> equation A
-----> equation B
Substitute equation B in equation A

square root both sides

Find the value of b
-----> 
step 2
Find the length of fencing
The perimeter of a rectangle is equal to

we have


substitute

Answer:
tan=0.75
Step-by-step explanation:
We know sin=opp/hyp, so 21 is the opposite side length in relation to theta.
To figure out tan, we need to know what the adjacent angle is because tan=opp/adj
21 squared= 441
35 squared =1225
1225-441= 784
The square root of 784 = 28
Now that we know both the opp and adj sides, we can solve for tan.
21/28= 0.75