# A planet requires 280 (Earth) days to complete its circular orbit around its sun, which has a mass of 6.5 x 10^30 kg. What are the planet's (a) orbital radius and (b) orbital speed?

I found: $r = 2 \times {10}^{11} m$ and $v = 5 \times {10}^{4} \frac{m}{s}$