Use pi times r^2. 4^2=16. 16 pi = 50.2654824574. round as needed. CLOSEST INCHES WOULD BE 50!!
1)
False, it represent range,
2)
False, It is a function
3)
True, c represent range
4)
x=20
C=20*20+5=405
It is a function, for amount we assigne one value.
[box] equals 1/2 (i think; check by dividing 0.8 by 0.4 on calculator, or 4/5 divided by 2/5 on fraction calculator... kind of obvious)
2. Mountain ranges would be your answer