# Session 29: Perimeter word problems
**Session Title** **Perimeter word problems**
Objective 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.
Concepts 1. Whiteboard and markers 2. Ruler or measuring tape 3. Chart with formulas for perimeter 4. Worksheet with practice problems 5. Geometry tools (optionals)
Materials required 1. A measuring tape or ruler 2. Paper and pencil 3. Classroom objects (benches, desks, windows, doors, etc.)
Methodology 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.
Session Duration 90 minutes
### 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(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** .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** 1.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** 1.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? Answer: Perimeter = 4 × 30 = 120 cm **C. Triangle Problem** 1.A triangle has sides that measure 6 cm, 7 cm, and 5 cm. What is the perimeter? Solution: Perimeter = 6 + 7 + 5 = 18 cm **2. 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? Answer: Perimeter = 7 + 9 + 6 = 22 feet **5. 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 **6. 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