Find the area of the part of the sphere x² + y² + z² = R² that lies within the cylinder x² + y² = r² and above the xy-plane.

(a) 2ΠR² (1 - {√R² - r²}/R)
(b) 2ΠR² (1 - {r² / R²})
(c) ΠR² (1 - {√R² - r²}/R)
(d) ΠR² (1 - {r² -/R²})