MENSURATION

• Mathematics
• Secondary Education

Area and Perimeter

WARM UP.........

 Area of a rectangle

Area of a circle.

Circumference of a circle

The value of pi

2𝝅𝒓

𝟐𝟐/𝟕 𝒐𝒓 𝟑.𝟏𝟒

 l×b

𝝅𝒓^𝟐

2(l+b)

Cylinder

What do you see common in these pictures?

As a part of  painting competition, Grade 8 students decided to participate in a bottle art competition. Initially, their task is to paint the curved face of each bottle using a white colour. They collected bottles and started to paint. If 10 bottles are to be painted, how much paint is required in total?

Curved Surface Area of a Cylinder.

Learning Objectives:

1)Derive the formula for CSA of Cylinder

2)Apply the formula to solve real life problems.

LO: Derive the formula for CSA of Cylinder

Instructions:

        1. Roll a rectangular sheet along its length and make in to a cylinder.

         2.   Compare the dimensions of rectangle and cylinder .

 

Activity:

LO: Derive the formula for CSA of Cylinder

The curved surface area of the cylinder = 

                                    r= base radius of the cylinder

                                    h = height of the cylinder

2πrh

What is the formula for finding the curved surface area of a cylinder?

1. 2πr
2. 2πrh
3. πr​2​​
4. πrh

The base radius of a cylinder is 7 cm and its height is 10cm.Find the curved surface area of the cylinder.

Curved Surface Area of a Cylinder.

Learning Objectives:

1)Derive the formula for CSA of Cylinder

2)Apply the formula to solve real life problems.

Activity-Choice Board

Activity 1-Wrapping Pencils

Take an A4 size paper and your pencil. 

Find the Area of A4 sheet and CSA of pencil.

How many such pencils you can wrap with the A4 sheet?

Activty :2-Notebook Page

Create your own notebook page that teaches others how to find the curved surface area of a cylinder. Your notebook page should

include a learning objective, definitions of important vocabulary words, and at least 2

practice problems. 

Activity 3:Frame and Solve

Create a real life situation and frame a question based on curved surface area of a cylinder and solve it.

Learning Objectives:

1)Derive the formula for CSA of Cylinder

2)Apply the formula to solve real life problems.

CHOICE BOARD

Extension Task

What is the total surface area of a cylinder?