Lesson plan of Perimeter and Area
Students` Learning Outcomes
- Identify the units for measurement of perimeter and area.
- Write the formulas for perimeter and area of a square and rectangle.
- Apply formulas for perimeter and area of a square and rectangle.
Information for Teachers
- Distance of around the closed ended shape is called its perimeter.
- Perimeter can be measured in the units of meter, centimeter and kilometre.
- Perimeter of a shape is calculated by adding length of all of its sides.
- Area is the amount of region that a shape cover i.e. Area = Length x Breadth
- Area can be measured in square units.
Material / Resources
Writing board, chalk / marker, duster, pencil, paper, scissors, text paper, ruler, chart paper cutouts with different shapes and sizes
Introduction
- Ask the students:
o What is an open ended and closed ended shape?
o What is perimeter?
o What is area?
o How can we measure “perimeter” and “area”?
- Discuss with the students that a perimeter and an area can be measured in m, cm, km etc. area is measured in square units.
- Ask students to walk in the ground and identify the perimeter and van area of a ground.
- Ask students to identify and point to the perimeter and area of their pencil box, teacher`s desk, and any note book.
Development
Activity 1
- Draw the following shape on the board.
- Ask them to find out the perimeter 5 of the shape. [Let them think and then check their answers]
- Perimeter can be 3 measured by adding lengths of a shape.
- Therefore the perimeter of the rectangle is 7 + 3 + 7 3 = 20 units.
- Ask the students to draw different size shapes to find perimeters.
- Divide class into groups of four members.
- Give each group drawings of different shapes of different sizes.
- Ask them to mention the name of shapes and find their perimeters.
- Appreciate for correct answers.
- Correct the wrong answers.
- Make it clear that a perimeter is found by adding length of all sides.
Activity 2
- Draw a rectangle like shape as shown on the board.
- Ask them about its perimeter.
- Tell them how we will find the length of the other 2 sides.
- In a rectangle opposite sides are equal, so to work out the perimeter of a rectangle you just need to know only the length and width.
- Look at the shape and find the length of each side. Add the lengths:
- Total length of all sides is 15 + 6 15 + 6 = 42. Now find the units.
- The lengths have been measured in centimetres, so the perimeter will also be measured in centimetres.
- The perimeter will be 42 centimetres.
Activity 3
Ask the students:
- What could be the easiest way to find the perimeter of a rectangle? Help them in concluding that since the 2 opposite sides of a rectangle are equal so if we add the length and breadth and multiply the sum by 2 then we can get perimeter.
- Formula for perimeter can also be written as:
o Perimeter of a rectangle = 2 x (l + b)
o Where l = length and b = breadth
- Ask them to apply the formula to different rectangular shapes and verify by adding all 4 sides.
- Ask what is the perimeter of a square having side –length 74 cm? Help them to conclude that:
- o Since a square has 4 sides of equal length, the perimeter of the square is 74 + 74 + 74 + 74 = 296. Or 4 x 74 = 296.
Ask the students:
- What could be the easiest way to find out the perimeter of a square?
- Help them to conclude that since all 4 sides of a square are equal we can find out its perimeter by multiplying one side of the square by 4 so, perimeter of a square = 4 x l. where l = length of a side of a square.
- In above example area = 4 x 74 = 296 cm
Activity 4
- Draw a square and rectangle on the board.
- Ask them to look at the shapes:
- How many squares is each divided into (4 and 12)
- If the side of each smaller square is 1 cm how much is the area of the square? 4 cm2(because it has 4 small 1 cm squares)
- What will the area of the rectangle? 12 cm2 (because it has 12 small 1 cm squares)
Activity 5
- Ask them to find out the area of the rectangle.
- Tell them the formula for area of rectangle
- The formula is:
- Area = l x b, where l = length and b = breadth.
- We know;
- l = 5
- b = 3, so Area = 5 x 3 = 15
Note:
- The area of a figure measures the size of the region enclosed by the figure. This is usually expressed in terms of some square unit.
- A few examples of the units used are square meters, square centimetres, square inches, or square kilometers.
- The area of rectangle is composed of its “width” and “length”. Explain few more examples to the students to make them understand about the concepts.
Area of Rectangle:
Sum up / Conclusion
PERIMETER VS AREA
- Formulas to calculate perimeter and area
Assessment
Individual Work:
- v Assign questions from the textbook to be done in individually and record for assessment and follow up.
- v Write the following on the board and ask students to solve.
- v Involve the students in solving the problems given in the end of the lesson of text book.
Follow up
- Assign questions from the textbook.
- Find out area of some square and rectangular objects in the house.
- Write down importance of finding area and perimeter.
