I need help plz help

The circumference of a circle is 5 pi cm. what is the area of the circle?

Aboat's value over time is given as the function f(x) and graphed below. use a(x) = 400(b)x + 0 as the parent function. which graph shows the boat's value increasing at a rate of 25% per year?

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)