Kepler's Third Law satellite problem

[bonekrushur]

Homework Statement

An orbiting satellite stays over a certain spot on the equator of (rotating) Pluto. What is the altitude (in km) of the orbit (called a "synchronous orbit")?

Homework Equations

r = [(G*M*T^2)/4pi^2]^(1/3)
h= r-radius of pluto

The Attempt at a Solution

I have plugged in the numbers (6.67e^-11) for G, (1.31e^22 kg) for M, and (551852 s) for T. I get (1.89e^7 m) for the radius. Then I subtract 1,153,000 meters from my answer to account for the radius of Pluto. My final answer in meters is (1.77e^7 m). My final answer in km is (1.77e^4 km). However, when I input this, the system shows this is wrong. I've tried several variations of the answer, but nothing works. Does anyone know if I've overlooked something in the equation? Thanks.

 

[ideasrule]

Seems right.

 

[Delphi51]

I get the same answer.