trying to find the total area between two rings

[steako]

i have the formula and it is A= pie *( R squared - r Squared)
but now that i have the answer i cant't figure out how to add up the total area since i am doing it for about 200 layers of rings.

so it is A= pie*(500 meters - 480 meters)

and i got 62.8 meters squared
which is 3943.84 meters

so to add the totals together do I add the "meters" togethers or the "squared meters" together to get my final total.

sorry if it is a simple answer, but I never finish geometry so i am a little lost
Thank you.

 

[wjm11]

so it is A= pie*(500 meters - 480 meters)

and i got 62.8 meters squared
which is 3943.84 meters

1) You cannot ever add things that have different units, for example, meters squared and meters.
2) You have made several errors in evaluating your formula. You must follow proper "order of operations" (PEMDAS).

Square the 500. Square the 480. Subtract. Multiply by pi (not pie).