PERIMETER

1. ALS FAMILY
Sir Shervin Rosopa
“Your future is created
by what you do today
not tomorrow”

4. LEARNING STRAND 3:
Mathematical and
Problem-Solving Skills
Measurement, Perimeter,
and Circumference

7. Different shape

8. How long is your fence if you
want to cover the whole farm?

9. FINDING PERIMETER

10. After studying this module, you should be
able to:
•Applies the formula for computing perimeter
(LS2CP/NS-NS-PSD-LE/AE/LS/AS-3)
•Explains the meaning of perimeter and its practical
applications in daily life (LS2CP/NS-NS-PSD-LE/AE-3.1)
•Computes the perimeter of different geometric
shapes in everyday life
(LS2CP/NS-NS-PSD-LE/AE/LS/AS-3.2)

11. THE
Examine closely the different shapes of polygons again. Count the sides of each
polygon.

12. TRIANGLE

13. Quadrilaterals

14. pentagon

15. hexagon

16. octagon

17. What do you notice about the name of the polygon
and the number of its sides?
Did you notice that the name of the polygon is
related to the number of its sides?

18. Perimeter

19. Perimeter
What is Perimeter?
The distance around a
two-dimensional shape.

20. Perimeter is the distance around the
outside edge of a flat object.
Perimeter is reported as a total
number of linear units.
The perimeter of a figure is the distance around it. To
find the perimeter you can add the lengths of the
sides.

21. How do we measure or
calculate it for different
geometric shapes?

22. Example
2
3
P = 10

23. 3 6
5 P = 14
Example

24. 4
4
4
P = 12
Example

25. 3
3
3
3
P = 12
Example

26. 8
8
P = 32
Example

27. Perimeter Formula
Rectangle
W
L
Perimeter
W = width
L = Length
2 x (W+L) = Perimeter

28. Perimeter Example
2 X (7 + 3) = 20
Rectangle
7
7
3
3
Perimeter

29. Perimeter Example
Or Just Add The Sides Together.
3 + 7 + 3 + 7 = 20
7
7
3
3
Perimeter

30. Perimeter Formula
Square
s
Perimeter
s = Length of Sides
4 X s= Perimeter

31. Perimeter Example
3 x 4 = 12
Square
3
3
3
3
Perimeter

32. Additional Example 1: Finding the Perimeter of
a Polygon
Find the perimeter of the figure.
2.8 + 3.6 + 3.5 + 3 + 4.3
Add all the side lengths.
The perimeter is 17.2 in.

33. Check It Out: Example 1
Find the perimeter of the figure.
3.3 + 3.3 + 4.2 + 4.2 + 3
Add all the side lengths.
3.3 in. 3.3 in.
4.2 in.
4.2 in.
3 in.
The perimeter is 18 in.

34. Additional Example 2: Using a Formula to Find
Perimeter
Find the perimeter P of the rectangle.
P = 2l+ 2w
Substitute 12 for l and 3 for w.
P = (2 • 12) + (2 • 3)
P = 24 + 6
P = 30
Multiply.
Add.
The perimeter is 30 cm.
12 cm
3 cm

35. Check It Out: Example 2
Find the perimeter P of the rectangle.
P = 2l + 2w
Substitute 15 for l and 2 for w.
P = (2 • 15) + (2 • 2)
P = 30 + 4
P = 34
Multiply.
Add.
The perimeter is 34 cm.
15 cm
2 cm

36. Let’s Try This
Compute for the perimeter of each of
the following squares having the given
length of side:
1. s = 8 m 3. s = 10.5 m
2. s = 12 m 4. s = 25 m

37. EXAMPLE : Ana is interested in buying the vacant lot beside her
house. The real estate broker informed her that the lot is 15
meters long and 10 meters wide. What is the perimeter of the
lot?
Solution:
• The given facts are: l = 15 m w = 10 m
• The problem is: What is the perimeter of the lot?
• Using the formula: P = (l × 2) + (w × 2)
• Substitute the values of l and w in the formula: P = (15 m × 2) + (10 m × 2)
= (30 m) + (20 m)
= 50 m
• Therefore, the perimeter of the lot is 50 meters.

38. EXAMPLE : A rice field is pentagonal in shape. The lengths of its sides
are 205 m, 115 m, 153 m, 187 m and 165 m respectively. If the owner
wants to fence it with three strands of barbed wire, how many meters of
wire in all will be needed?
Solution: To find the total number of meters of barbed wire needed to
fence the pentagonal rice field, you have to compute for the perimeter
of the rice field. Given the measurement of the sides of the field, it
would look like this:
To get its perimeter, simply add all its sides:
205 m + 187 m + 165 m + 153 m + 115 m = 825 m

39. The perimeter of the field is 825 m. But the owner wants to fence it with 3
strands of barbed wire. To get the total number of meters of barbed wire
needed, we multiply the perimeter by 3. Therefore, 825 m × 3 = 2475 m.

40. EXAMPLE: Find the perimeter of the triangle below.
Your solution: To find the perimeter, ______________
So, ______________ = _______________
Therefore, P = _______________

41. Let’s Review
Find the perimeter of each of the following:
1. A garden 15 meters long and 12 meters wide
2. A lot 10 meters long and 7 meters wide
3. A swimming pool 20 meters long and 12 meters wide
4. The town park 45 meters long and 32 meters wide

42.  The perimeter of a polygon is the sum of the
measurements of all its sides.
 For a rectangle, P = (l × 2) + (w × 2)
where P = perimeter of a rectangle
l = measure of the length
w = measure of the width
 For a square, P = 4s
where P = perimeter of a square
s = measure of a side of a square
Square
Rectangle

43. A. Measurement of different object inside of the house that forms geometric shape like
(DOOR, WINDOW, FLOOR, HOUSE FENCE) With picture or sketch of the object.
Rubric
5points – Correct measurement with complete solutions and unit and contain picture or
sketch as evidences.
4points - Correct measurement with complete solutions but no unit and contain picture
or sketch as evidences.
3points - Correct measurement with few solutions and contain picture or sketch as
evidences.
2points – Incorrect measurement with few solutions and contain picture or sketch
1point- sketch or picture only

44. B. Solve the following problems. Write your computations on a separate
sheet of paper.
1. Find the perimeter of a dining table 3 meters long and 1 meter wide.
2. Karina bought a residential lot that is 24 meters long and 22 meters wide.
How many meters of wire will she need to fence her lot?
3. Lancelot’s garden is 28 meters long and 25 meters wide. How many
meters of cyclone wire will be needed to fence his garden?
4. Kadita’s son has a small tilapia pond that is 8 meters long and 6 meters
wide. How many meters of rope will be needed to enclose the fish pond?

46. ASSESSMENT

47. A. Write the names of
the polygons in the
spaces provided.

48. B. Solve the following word problems.
1. There are two lots for sale. Lot A is 18
meters long and 12 meters wide while Lot B
is 19 meters long and 11 meters wide. Which
lot will require a longer barbed wire to fence
it?

49. B. Solve the following word problems.
2. How many meters of rope will Jimmy need
to enclose a play area for children that is 12
meters long and 10 meters wide?

50. B. Solve the following word problems.
3. A barangay health center is 9 meters long
and 7 meters wide. What is its perimeter?

51. B. Solve the following word problems.
4. Behind the health center is a herbal
garden that grows aloe vera, oregano and
basil. The garden is 12 meters long and 8
meters wide. What is its perimeter?