Help with a puzzle

Here.

I have all but C, H, I and J.
I think C has something to do with this, but it’s above my math skills.
And I believe that the first part of J is ‘e’,but I couldn’t get the Austrailia part.

The answer to each of these will be a number.
Can anyone help me out with these and explain what I’m missing? Thanks!

Update: I just figured out I.

The Australia map looks to me like they’re focusing on the bay, which is called the Great Australian Bight.

Yep got J. Thanks

Got C, just need H!

Hmmm, I think I got C, is it 3?

H has Bill Gates getting pie in the face, so I guess it’s something times pi. I don’t know who the other guy is, though.

I don’t get C.

Isn’t the other guy Zero Mostel? Zero times pi is . . . undefined.

No, 0 x pi=0.

What digit is left? I didn’t do the other ones, but if zero hasn’t come up yet, then…

That’s got to be it, thanks.

0 times any defined number is always 0.

pi is defined. It’s just not rational. But it is the ratio of the circumference of a circle to twice its radius.