Students often refer to Class 5 Maths Notes and Chapter 11 Grandmother’s Quilt Class 5 Notes during last-minute revisions.
Class 5 Maths Chapter 11 Notes Grandmother’s Quilt
Class 5 Maths Notes Chapter 11 – Class 5 Grandmother’s Quilt Notes
Every shape around us has a size and a boundary. When we spread out a mat on the floor or put a fence around a garden, we are thinking about area and perimeter. The area tells us how much space a shape covers, while the perimeter tells us how long its boundary is. The sum of the lengths of all sides of a shape or a figure is called perimeter.
→ The distance around the edges of a closed figure or a shape is called the perimeter.
- Perimeter of a closed figure = Sum of the lengths of its all sides
- Perimeter of a rectangle = 2 × Length + 2 × Breadth
- Perimeter of a square = 4 × Length
→ Area is the amount of surface that a plane-closed figure covers.
- Area of a rectangle = Length × Breadth
- Area of a square = Length × Length
- The area of a square with sides 1 unit is 1 square unit (sq. unit)
→ We can calculate the area of a shape by placing the shape on a square grid.
Perimeter of a Shape
→ The length of the border of a shape is called the perimeter of the shape. e.g. The perimeter of the shape A B C D E is AB + BC + CD + DE + EA units.
→ Note: The perimeter of any shape is measured in units, metres, centimetres, etc.
Area
→ The region or space covered by a shape is called the area of the shape. e.g. The area of the shape ABCDE is shaded.
→ Note The area of any shape is measured in square units, square metres, square cm, etc.
→ Finding Perimeter of Any Shape Using Square Grid
→ The perimeter of any shape drawn on a square grid can be determined by counting the length of the boundaries of the shape along the grid lines.
→ e.g. The perimeter of the given shape is 22 units.
Finding Area of Any Shape Using Square Grid
Using square grids is the most convenient way to find the area of regions as well. The area of any shape drawn on square grid is equal to the number of small squares covered by the shape, because the area of a square with sides 1 unit is 1 square unit. e.g.
→ The area of the region AB CD EF is 14 square units because 14 small squares are being covered by the given shape.
Formulas Related to Square and Rectangle
→ The perimeter of a rectangle having length l and breadth b is 2(l+b) units.
→ The perimeter of a square having side s units is 4 × s units.
→ The area of a rectangle having length l and breadth b is l × b square units.
→ The area of a square having side s units is s<sup>2</sup> square units.