The artwork that follows shows the dimensions of the various parts of Earth, from its crust to its inner core. Use a thickness of 15 miles for the crust.

(a) Determine the radius of Earth in miles.

(b) Determine the radius of Earth in kilometers.

(c) The deepest hole dug in Earth, called the Kola Well, was in the Kola Peninsula in northwest Russia. The Russians dug the well for 27 years before stopping because the high internal temperature of Earth was melting their drills. The deepest the hole reached was about 12.2 km.  How far down, in miles, did the hole reach? 

(d) At the location of the hole, the crust was about 24 km. How thick was the crust at that location in miles?

When necessary round your answers to the nearest hundredth.