We use direct proportionality:
360⁰......Pi×R² (full circle)
120⁰.......x
x=120×pi×R²/360=pi×R²/3
x=pi×4²/3=16.76mi²
A=3×pi cm², for an angle of 2×pi/3=120⁰
In a similar way we compute the area of the full circle:
360.........x
120..........3×pi
x=3×pi×360/120=9×pi=3²×pi.
Thus the radius is 3cm.
velocity is the slope (which can be calculated after finding the derivative) → given function f(x), velocity = f'(x).
acceleration is the slope of the velocity (which can be calculated after finding the derivative of the velocity) → given function f(x), acceleration is f''(x)
**************************************************************************************************
1a) A → B
f(x) = 
f'(x) = 
1b) B → C
f(x) = 
f'(x) =
= -5
1c) C → D
f(x) = 20
f'(x) = 0
Hope this helps!
x=15-657/2=15-373/2=-5.316
x=15+657/2=15+373=20.316
The answer should be the very last option. An equation where the highest exponent of the variable (usually x) is a square (2).