Why are there a 10 to the power 9 nanoseconds in an hour?

Answer 1

There are not.

1 nano second = 10^-9 second → 1 s = 10^9 ns.

There are 3600 seconds in 1 hour → 1 hour = 3600 s = 3600 × 10^9 ns = 3.6 × 10^12 ns.

Answer 2

There aren't. The calculation just doesn't work out.