The length of a side of a square is 6.81 cm, correct to 3 significant figures. What is the perimeter of the square to an appropriate degree of...

The length of the side of the square is 6.81 correct to 3
significant places, that implies we can write the length as 6.810
cm.

The perimeter of the square is 6.810*4 = 27.240 cm. As
the length of the side is known to an accuracy of 3 significant places, the perimeter
too is accurate to 3 significant places.

The lower bound of
the perimeter is the number with one extra significant figure that when rounded up would
yield 27.240. Here it is 27.2350 cm.

The
lower bound of the perimeter is 27.2350 cm.