1. The perimeter of a shape is the total length of its boundary.
2. The problem gives a square with a side length of 3 cm. The perimeter of this square is 3 cm + 3 cm + 3 cm + 3 cm = 12 cm.
3. The shapes in the worksheet are all made up of the same 3 cm by 3 cm squares.
4. To find the perimeter of each shape, we need to count the number of 3 cm edges that form the outside of the shape.
5. For shape a, it is a 3 cm by 3 cm square. It has 4 sides, each 3 cm long. The perimeter is 4 × 3 cm = 12 cm.
6. For shape b, we count the outer edges. There are 8 edges of 3 cm each. The perimeter is 8 × 3 cm = 24 cm.
7. For shape c, we count the outer edges. There are 10 edges of 3 cm each. The perimeter is 10 × 3 cm = 30 cm.
8. For shape d, we count the outer edges. There are 8 edges of 3 cm each. The perimeter is 8 × 3 cm = 24 cm.
9. For shape e, we count the outer edges. There are 10 edges of 3 cm each. The perimeter is 10 × 3 cm = 30 cm.
10. For shape f, we count the outer edges. There are 12 edges of 3 cm each. The perimeter is 12 × 3 cm = 36 cm.
11. For shape g, we count the outer edges. There are 10 edges of 3 cm each. The perimeter is 10 × 3 cm = 30 cm.
12. For shape h, we count the outer edges. There are 12 edges of 3 cm each. The perimeter is 12 × 3 cm = 36 cm.
13. For shape i, we count the outer edges. There are 8 edges of 3 cm each. The perimeter is 8 × 3 cm = 24 cm.
The perimeters of the shapes are:
a. 12 cm
b. 24 cm
c. 30 cm
d. 24 cm
e. 30 cm
f. 36 cm
g. 30 cm
h. 36 cm
i. 24 cm
Parent Tip: Review the logic above to help your child master the concept of perimeter of shapes worksheet.
