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**nazz** Question

The length of a side of a square is 6.81 cm, correct to 3 significant figures.

(a) Work out the lower bound for the perimeter of the square.

(b) Give the perimeter of the square to an appropriate degree of accuracy.

You must show working to explain how you obtained your answer.

Ans a)

3 significant figures, hence subtract 0.005 from 6.81 to get 6.805cm (lower bound)

Lower bound for the perimeter is 6.805X 4= 27.22cm.

b).

Upper bound for the perimeter is 6.815X4= 27.26cm.( 6.81+0.005= 6.815)

Appropriate degree of accuracy =27cm ( as i was told) , did not understand why. Can someone shed some light on this.