# 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

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.
• 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.

• 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

• 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.

• 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.