Answer:
D
Step-by-step explanation:
given A = π(R² - r²)
divide both sides by π, hence
R² - r² = [tex]\frac{A}{\pi }[/tex]
add r² to both sides
R² = [tex]\frac{A}{\pi }[/tex] + r²
Take the square root of both sides
R = [tex]\sqrt{A/\pi+r^2 }[/tex] → D
