Answer:
about 7500 km
Step-by-step explanation:
The mass of planet Katar is 7.27×10^25 kg. The force on the kangaroo is given by ...
F = GmM/r^2
Solving for r, we have ...
r = √(GmM/F) = √(6.67×10^-11 × 78.2 × 7.27×10^25 / 6742) ≈ √(5.62×10^13)
This is in meters, so the radius in km is about ...
r ≈ 7500 km