Question 1

Question 1: If the length and breadth of a rectangle are doubled, how many times the perimeter of the old rectangle will that of the new rectangle be?

Accepted Answer

Let the length of the old rectangle be l and breadth be b. ∴ Perimeter of old rectangle = 2(l + b) Length of new rectangle = 2l and breadth = 2b ∴ Perimeter of new rectangle = 2(2l + 2b) = 2 x 2 (l + b) = 2 x perimeter of old rectangle ∴ The perimeter of new rectangle will be twice the perimeter of

Question 2

Question 2: If the side of a square is tripled, how many times the perimeter of the first square will that of the new square be?

Accepted Answer

Let the length of the square be a. Perimeter of square = 4 x side = 4 x a = 4a Side of new square = 3 x a = 3a Perimeter of new square = 4 x side = 4 x 3a = 3 x 4a = 3x perimeter of original square. ∴ The perimeter of new square will be three times the perimeter of original square.

Question 3

Question 3: Given alongside is the diagram of a playground. It shows the length of its sides. Find the perimeter of the playground.

Accepted Answer

Side AF = side BC + side DE ∴ Side AF = 15 + 15 = 30 m Side FE = side AB + side CD ∴ Side FE = 10 + 5 = 15 m ∴ Perimeter of the playground = side AB + side BC + side CD + side DE + side FE + side AF = 10 + 15 + 5 + 15 + 15 + 30 = 90 m. ∴ The perimeter of the playground is 90 m.

Question 4

Question 4: 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 t

Accepted Answer

Side of the square piece of cloth = 1 m ∴ Side of each napkin = 0.5 m Length of lace that will be required for 1 napkin = perimeter of the napkin = 4 x side = 4 x 0.5 = 2 m ∴ Perimeter of 4 napkins = 4 x 2 = 8 m ∴ 8 metre long lace will be required to trim all four napkins.

Chapter 12 Perimeter and Area Practice Set 44 Solutions