1 mile = 5280 feet which means the plane is flying at an altidude of 4.5 miles currently other than that refine your question.
Brianna's thinking is incorrect.
Expessions A, and C. are equivalent.
For C, you add 5x and x together (because they have the same variable) to get 6x - 4.
For A, you subtract 9x and 3x (because they have the same variable) to get 6x- 4.
(10x+20)+(32+6x)=180
52+16x=180
16x=128
x=8
A=100 degrees
Plug 7/50 into your calculator to get 0.14. The answer is C.
