is 39.0625 right ??
Yes, but you need the correct significant figures, which is 3. So the answer should be 39.1 ft^2 (don't forget your units!) If you forget your significant figures rules check this link: http://www.usca.edu/chemistry/genchem/sigfig.htm
And very well done! hehe.
so my zero is not significant and should e replaced with a 1 ??
Not quite, significant figures it kinda like saying to how many digits should you round to. You were given 6.25 feet. These are all non 0 numbers thus ALL significant so we count how many we have... we have 3 significant digits here. Now we do our math and get our answer \[(6.25 Feet)^2 = 39.0625 Feet^2\] Now the answer has more than 3 significant digits which would make someone thing our measurements were more accurate than they actually were! So we count three digits in (they are all significant) and round. To answer your last reply specifically though, the 0 in the answer would be considered significant still because it's surrounded by non 0's! Sig Figs get wayyyy easier in time (I still mess them up though occasionally lol)
So to sum this up, we were given a measurement with 3 sig figs. So our answer should be in 3 sig figs. THUS we round to 3 sig figs after we get the answer.
ohh so I need to include my feet^2
Yep! That's your units. It's not the same unit as Feet anymore. Feet^2 are not equal to Feet.
ok I get it thank you