Yeah that's what I was thinking bu thtis question was left as a challenge meaning that there must be something that can be done. I'd like to point out that it says the planet's orbit is a perfect circle.
Homework Statement
A planet orbiting a star experiences a force of magnitude 3x1022N due to gravitational attraction to the star. If the planet has a speed of 2x107 m/s to complete on orbit, calculate the mass of the planet and radius of the orbit? Assume the orbit to be a perfect circle...