Final answer:
To solve for p in the formula for the area of a circular ring, divide the area by 4πr² and rewrite the equation as p = A / (4πr²). When A = 905 ft² and r = 9 ft, p ≈ 3.171 ft.
Step-by-step explanation:
To solve for p in the formula for the area of a circular ring, we can rearrange the formula to isolate p. The formula for the area is A = 4πr². To solve for p, divide both sides of the equation by 4πr² and rewrite the equation as p = A / (4πr²).
In this case, we are given A = 905 ft² and r = 9 ft. Plugging these values into the equation, we have p = 905 / (4π(9)²). Simplifying the expression, we get p ≈ 3.171 ft.