Part A: To find how much the sun produces in 2.45 ·

, we need to multiply the rate per second by the number of seconds we want the answer to have. This gives us:
2.45 ·

· 3.9 ·

=
= 9.555 ·

That gives the answer of 9.555 ·

ergs
Part B: The more reasonable measurement of the diameter of a blood cell is 7.4 ·

mm. That's because by saying the diameter of a blood cell is 7.4 ·

mm, you are saying the diameter is 7.4 meters!