Trigonometry and Unit Circles Test Corrections

I found the concepts in this unit to be relatively easy, with the exception of the one displayed in problem 4. I struggled, however, when it came to memorizing the unit circle. I knew the positives and negatives, but not the exact numbers, which hurt me on question 9.

4.
tan50.57= y/x
x= y/tan50.57
tan70.42=(y+3500)/x
x=(y+3500)/tan70.42
y/tan50.57= (y+3500)/tan70.42
y(tan70.42)= (y+3500)(tan50.57)
y(tan70.42)= y(tan50.57) +4256.42
2.81y= 1.22y +4256.42
1.59y= 4256.42
y=2676.99
+3500
6176.99 feet

8.
secx= -5/3
cos x= -3/5
hypotenuse: 5
adjacent: -3
opposite: -4
sin= -45
tan: 4/3