power 4dPower of the lens (P) = 4 D. Refractive Index (r) = 1.5. To Find: The radius of curvature. Calculations: The following equation determines a lens's power: where P is the power ofCheck 4D, 5D, 6D, Jackpot results, Sports Toto (Star, Power, Supreme Jackpot), Magnum Jackpot, Damacai 1+3D Jackpot, Live from Malaysia.