Answer:
The radius is about 64 times bigger.
Step-by-step explanation:
Earth's radius is more or less 6,400 km (close to 4 000 miles), depending on the estimations and where on Earth you measure the distance to the core (since the planet isn't exactly round and the surface isn't flat all around).
The Karman Line is set at 100 km (about 62 miles), although other measures are used by other organizations to determine the beginning of space around the planet.
So Earth's radius is about 64 times bigger than the distance defined for the Karma Line.