Stephenson G. answered 06/27/24
Experienced Calculus Tutor: College, AP Calculus AB, AP Calculus BC
Given inner radius Rinner and the radial width ΔR, treat the ring as a thin circular annulus and calculate its area.
Area of a circle is A = πr2. Using differentials, area of the annulus is:
dA = 2πRinner*ΔR
dA = 2π * 62,900 * 50 = 19,795,400 km2 (approximately)
So, the area of the ring is approximately 19,795,400 km2.
Hope this was helpful.