2. The Kepler's third-law constant of proportionality for the Sun, Cs, is 3.4 x 10" m'/s'. If Earth's radius of orbit is doubled, then Cs would become a. 4.2 x 10 7 m /s d. 1.4 x 1019 m'/s' b. 8.5 x 10'7 m'/s e. 2.7 x 10'9 m'/s c. 3.4 x 1018 m)/s] 3. Kepler's constant for the Sun is Cs = 3.4 x 10" m'/s'. The average period of orbit for Earth is 365.26 d. The average radius of Earth's orbit is a. 7.7 x 10 km d. 1.5 x 10" m b. 3.4 x 10" m e. 5.8 x 1015 m c. 1.8 x 10 0 m