Question

As shown in the figure, four napkins all of the same size were made from a square piece of cloth of length 1 m. What length of lace will be required to trim all four sides of all the napkins ?

Answer 1

Length of each side of a square piece of cloth = 1 m
Now, four napkins all of same size were made from this square piece of cloth.
∴ Length of each side of a napkin, s = Length of each side of a square piece of cloth ÷ 2
= 1 ÷ 2
= $\frac{1}{2}$ m
Length of lace needed to trim all the four sides of a napkin = perimeter of a napkin
= 4 × s
= 4 × $\frac{1}{2}$
= 2 m
∴ Length of lace needed to trim all the four sides of four napkins = 4 × length of lace needed for a napkin
= 4 × 2
= 8 m