What is the perimeter and area of the new shape? ? original square has side=9cm

Hey there :)

           9 cm
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|                             |    9 cm
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a) Formula of the perimeter of a square is 
P = 4 x side
   = 4 x 9
   = 36 cm

b) Formula of the area of a square is
A = side²
   = 9²
   = 81 cm²

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Small squares are  the side of the original square
x 9 = 3 cm

The perimeter of one small square =
P = 4 x 3 = 12 cm

Perimeter of 4 squares = 4 x perimeter of one square = 4 x 12 = 48 cm

The area of one small square =
A = 4² = 16 cm²

Area of 4 squares = 4 x area of one square = 4 x 16 = 64 cm²

c) Perimeter of new shape
Perimeter of original square + perimeter of 4 squares
36 + 48
84 cm

d) Area of new shape
Area of original square + area of 4 squares
81 + 64
145 cm²