what is the area, and its approximate uncertainty, of a square of side 3.1x10^4 cm?

1 answer

(3.1*10^4)^2 = 9.6*10^8

3.1^2 ----> 9.6 to two significant figs
but it might have been
3.05^2 ----> 9.3
or maybe
3.1499999999...^2 ---> 9.9

so
9.6 + or - .3 * 10*8