Geometry - Finding Perimeters of 2D shapes

WALT find the Perimeter of 2D shapes

Formulae:

Perimeter of a Square = side + side + side + side or 4 x side

Example: The perimeter of a square of side  5cm = 5 + 5 + 5 + 5 = 20 cm or 4 x 5 = 20 cm

Find the perimeter of the following squares:

The perimeter of a square of side  10 cm = 10 x 4 = 40 

The perimeter of a square of side  25cm = 25 x 4 = 100

The perimeter of a square of side  5m = 5 x 4 = 20m

The perimeter of a square of side  50m = 50 x 4 = 200m

The perimeter of a square of side  1km = 1 x 4 = 4km

Perimeter of a Rectangle = length + width + length + width or 2 x l + 2 x w

Example: The perimeter of a rectangle whose length is 6cm and width is 4cm = 6 + 4 + 6 + 4 = 20 cm or 2 x 6 + 2 x 4= 12 + 8 = 20 cm

Find the perimeter of the following rectangles whose lengths and widths are given below:

Rectangle 1 - length is 8cm and width is 5cm

Perimeter =  (5 x 2 = 10 8 x 2 = 16) = 26

Rectangle 2 - length is 10cm and width is 7cm

Perimeter =  (10 x 2 = 20  7 x 2 = 14) = 34

Rectangle 3 - length is 8m and width is 6m

Perimeter =  (8 x 2 = 16   6 x 2 = 12) = 28

Rectangle 4 - length is 16m and width is 10m

Perimeter =  (16 x 2 = 32   10 x 2 = 20) = 52

Rectangle 5 - length is 4km and width is 2km

Perimeter =  (4 x 2 = 8   2  x 2 = 4) = 12

Evaluation: Today I learnt what a perimeter is and what the value of it.