The are is the whole area minus the inner:
(z+4)(z+4)-(z)(z)
Expand:
z^2+8z+16-z^2
Simplify:
8z+16
Answer:
8z+16 OR 8(z+2)
The first one is A and the second one is C
Exterior would be 360
interior 180
The slope of the green line would be 1/2
Perpendicular lines have opposite and reciprocal slopes. This means we first have to take the -2 and make it opposite to its current sign (2). Now we can take the 2 and flip it as a fraction (1/2).
This gives us the slope
You should get 375 seconds which is 6 1/4 of a minute or 6 minutes and 15 seconds