Jason is comparing the sizes of Earth and Saturn. The radius of Earth is approximately 6,378,100 meters. What is the radius of Earth, in meters, written as a single-digit number multiplied by a power of 10?

Renee hiked for 6 3/4 miles. after resting, renee hiked back along the same route for 5 1/4 miles. how many more miles does renee need to hike to return to the place where she started? represent your answer as a simplified mixed number, if necessary.