# Session 29: Perimeter word problems

<div align="left" dir="ltr" id="bkmrk-session-title-perime"><table style="width: 116.785714%; height: 374.875px;"><tbody><tr style="height: 29px;"><td class="align-center" style="width: 26.350531%; height: 29px;">**Session Title**

</td><td class="align-center" style="width: 73.649469%; height: 29px;">**Perimeter word problems**

</td></tr><tr style="height: 135.625px;"><td style="width: 26.350531%; height: 135.625px;">Objective

</td><td style="width: 73.649469%; height: 135.625px;">1. By the end of this lesson, students will be able to:
2. Define perimeter and understand its significance.
3. Calculate the perimeter of various shapes, including squares, rectangles, and irregular polygons.
4. Apply perimeter concepts to real-life situations.

</td></tr><tr style="height: 17.421875px;"><td style="width: 26.350531%; height: 17.421875px;">Concepts

</td><td style="width: 73.649469%; height: 17.421875px;">1. Whiteboard and markers
2. Ruler or measuring tape
3. Chart with formulas for perimeter
4. Worksheet with practice problems
5. Geometry tools (optionals)

</td></tr><tr style="height: 86.828125px;"><td style="width: 26.350531%; height: 86.828125px;">Materials required

</td><td style="width: 73.649469%; height: 86.828125px;">1. A measuring tape or ruler
2. Paper and pencil
3. Classroom objects (benches, desks, windows, doors, etc.)

</td></tr><tr style="height: 77px;"><td style="width: 26.350531%; height: 77px;">Methodology

</td><td style="width: 73.649469%; height: 77px;">1. Direct Instruction: The Teacher introduces the concept of perimeter with examples and uses diagrams.
2. Hands-on Practice: Students work on exercises individually or in pairs to calculate the perimeter of different shapes.

</td></tr><tr style="height: 29px;"><td style="width: 26.350531%; height: 29px;">Session Duration

</td><td style="width: 73.649469%; height: 29px;">90 minutes

</td></tr></tbody></table>

</div>### Introduction activity (10 minutes):

1. Engage students: Ask, “What do you think ‘perimeter’ means?”
2. Hook Question: “If you walked all the way around your backyard, what are you measuring?” (Introduce the idea of perimeter.)
3. Define Perimeter: The distance around a 2D shape.
4. Show visuals of different shapes and identify their sides.

### Main Activity (70 minutes):

**Teach formulas: (10 minutes)**

**Rectangle: P = 2(l + w)**

![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXdWM51Kb5-tLP_7HzaNwanFdFKpceLeRcP_q6S6Yt7_W3D3CkjjIs5rpO_Kno9UemmJUK4dw7FGb-xWYbiRGRHeuSIfphuLwF0X3auAoScRHjcpPjSA-9R_03e5Ml7jDXTZ8IFaeHmiuxqfbR4DpA?key=wsEQNNOqnZNrSPYKMSvETwQh)

**Square: P = 4 × side**

![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXfHlIACXSHMsbk__ys6BK-rihdvXBVe-j5OO9hY6Wjnsm4J7MemyGmcIPbN3Yq-urGJlEi_dctHnRxlJoWdVzeGep6tav0hJHIxfMvFgSswhbM3Z1HwdE7Cz6yqD58sl89tZfZhIwsfXBXa_kFu3eU?key=wsEQNNOqnZNrSPYKMSvETwQh)

**Triangle: P = a + b + c**

![](https://lh7-rt.googleusercontent.com/docsz/AD_4nXexyIOTTmIIPl6SfjGWzRrFb6FAkUiC-XkaWgu1qCGVTZHFeSa8f0wxksK1yox2KKVn3IN2NET2vY8sOiH6e-u-tcTKsTpqlmCh6WJrtu1vjamWOBDwrOCNxMSV67MEo3Jm9CKfzqyeQyZ4rwzNMPQ?key=wsEQNNOqnZNrSPYKMSvETwQh)

Use real-life examples: **(15 minutes)**

**1. Fencing a garden Problem: Rectangle Garden**

Sarah wants to put a fence around her rectangular garden. The length of the garden is 8 meters and the width is 5 meters.

**Question:** What is the total length of fencing Sarah needs?  
**Answer:** Perimeter = 2 × (Length + Width) = 2 × (8 + 5) = 2 × 13 = 26 meters

**2. Square Chalkboard Problem:**

A chalkboard in the classroom is square and each side measures 5 feet.

**Question:** What is the total length of trim needed to go around the board?  
**Answer:** Perimeter = 4 × 5 = 20 feet

**3 Triangle**

**Question:** A triangle has sides that measure 6 cm, 7 cm, and 5 cm. What is the perimeter?  
**Solution:** Perimeter = 6 + 7 + 5 = 18 cm

#####  

##### Independent Practices (25 minutes)

**Rectangle Problem** A rectangle has a length of 8 cm and a width of 5 cm. What is its perimeter?

Solution:  
Perimeter = 2 × (length + width) = 2 × (8 + 5) = 2 × 13 = 26 cm

**Square Problem** Each side of a square is 9 meters. What is the perimeter of the square?

Solution:  
Perimeter = 4 × side = 4 × 9 = 36 meters

**Square Tile** One square floor tile has sides that measure 30 cm.

Question: What is the perimeter of the tile?

Solution:   
Perimeter = 4 × 30 = 120 cm

**Triangle Problem** A triangle has sides that measure 6 cm, 7 cm, and 5 cm. What is the perimeter?

Solution:  
Perimeter = 6 + 7 + 5 = 18 cm

**Triangular Flower Bed** A triangular flower bed has three sides that measure 7 feet, 9 feet, and 6 feet.

Question: What is the total length of the fencing needed for the flower bed?

Solution:  
Perimeter = 7 + 9 + 6 = 22 feet

**Irregular Shape Problem** A shape has sides measuring 3 cm, 4 cm, 5 cm, 2 cm, and 6 cm. What is the total perimeter?

Solution:

Perimeter = 3 + 4 + 5 + 2 + 6 = 20 cm

**Missing Side Problem** A rectangle has a length of 14 m. The perimeter is 46 m. What is the width?

Solution:  
Perimeter = 2 × (length + width)

46 = 2 × (14 + width)  
46 = 28 + 2 × width  
46 - 28 = 18  
2 × width = 18 → width = 9 meters

#####  

##### Game Time (20 minutes)

**Instruction:**

- Ask the children what they see in the farmhouse.
- Give them only the questions you have given them, and explain the questions in a way that will lead them to the answer.
- These problems should be divided into 4 papers and given to each group.
- Divide them into four groups and give the same topics to two groups..

1. Group 1 - farm house
2. Group 2 - classroom
3. Group 3- farm house
4. Group 4- classroom

**Farmhouse related problems**

**1. Fencing or Walls**

Problem: You want to fence the entire perimeter of your farmhouse which is 100m long and 60m wide.  
Question: How much fencing is needed?  
Solution: Perimeter = 2 × (100 + 60) = 320 മീറ്റർസ്

**2. Gates**

Problem: You plan to install a gate on each side of a square farmhouse (each side 75 meters).  
Question: What is the distance between each gate if equally spaced?  
Solution: Perimeter = 4 × 75 = 300 meters  
Distance between gates = 300 ÷ 4 = 75 meters

**3. Paths or Roads**

Problem: A walking path is to be laid around the edge of the farmhouse (perimeter = 280 meters).  
Question: If it costs ₹50 per meter to build the path, what is the total cost?  
Solution: 280 × 50 = ₹14,000

**4. Animal Pens or Shelters**

Problem: You plan to build 3 animal pens along one 90-meter side of the perimeter, spaced equally.  
Question: How long is each pen (if no space between)?  
Solution: 90 ÷ 3 = 30 meters per pen

**5. Hedges or Trees**

Problem: You are planting trees every 10 meters along a 240-meter perimeter.  
Question: How many trees do you need?  
Solution: 240 ÷ 10 = 24 trees

**6. Water Channels or Ditches**

Problem: You want to dig a drainage ditch along the full perimeter (300 meters).  
Question: How much digging is required?  
Solution: 300 meters of ditch

**Classroom related problems**

**1. Walls**

Problem: The classroom is rectangular, with a length of 8 meters and a width of 6 meters.  
Question: What is the perimeter of the classroom?  
Solution: Perimeter = 2 × (8 + 6) = 2 × 14 = 28 meters

**2. Doors**

Problem: There are 2 doors in the classroom, each measuring 1.5 meters wide. If the total perimeter of the classroom is 28 meters.  
Question: What is the total width of the doors compared to the perimeter?  
Solution: Total width of doors = 2 × 1.5 = 3 meters. The doors take up 3 meters of the perimeter.

**3. Windows**

Problem: There are 4 windows, each 2 meters wide, placed along the perimeter of the classroom.  
Question: What is the total width of all the windows?  
Solution: Total width of windows = 4 × 2 = 8 meters

**4. Blackboard/Whiteboard**

Problem: The classroom has a whiteboard that is 3 meters wide. If you want to place a frame around the whiteboard,  
Question: What is the perimeter of the frame?  
Solution: Perimeter = 2 × (3 + 1) = 2 × 4 = 8 meters (assuming a 1-meter height for the whiteboard).

**5. Decorations or Charts**

Problem: You plan to hang charts along 3 walls, with each wall being 5 meters long.  
Question: What is the total length of the walls where charts will be hung?  
Solution: Total length = 3 × 5 = 15 meter

The team that completes the problems first will win

### Review Questions (5 minutes):

### Follow up Task (5 minutes):

**Home Work**

**Rectangle Garden:**  
Lena is planting a rectangular garden that is 9 meters long and 6 meters wide.

Question: How much fencing will she need to go around the garden?  
Answer: Perimeter = 2 × (9 + 6) = 2 × 15 = 30 meters

### Expected Learning Outcome 

**Knowledge building**

- Formulas for Perimeter
- Definition of Perimeter
- Properties of Shapes

**Skill building**

- Reading and Understanding Word Problems
- Calculation Accuracy
- Choosing the Right Formula