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# Q.17 Avneet buys 9 square paving slabs, each with a side of 1 / 2 m. He lays them in the form of a square. (a) What is the perimeter of his arrangement [fig 10.7(i)]? (b) Shari does not like his arrangement. She gets him to lay them out like a cross. What is the perimeter of her arrangement [(Fig 10.7 (ii)]? (c) Which has greater perimeter? (d) Avneet wonders if there is a way of getting an even greater perimeter. Can you find a way of doing this? (The paving slabs must meet along complete edges i.e they cannot be broken.)

(a) Side of square = 3 × side
= 3 × $$\frac{1}{2}$$
= 3 / 2 m
Perimeter of Square = 4 × $$\frac{3}{2}$$
= 2 × 3
= 6 m
(b) Perimeter = 0.5 + 1 + 1 + 0.5 + 1 + 1 + 0.5 + 1 + 1 + 0.5 + 1 + 1
= 10 m
(c) The arrangement in the form of cross has greater perimeter
(d) Perimeters greater than 10 m cannot be determined.