Correct Answer - Option 1 : 8√ 11 cm

**Given**

The perimeters of two squares are 48 cm and 40 cm

Area of third square is equal to difference of area of the two square

**Formula used**

Perimeter of square = 4 × side

Area of square = (side)^{2}

**Calculation**

Let side of square 1 = x

Perimeter of square 1 = 48 cm

⇒ 4x = 48

⇒ x = 12cm

⇒ Area = (12)^{2}

⇒ 144 cm^{2}

Side of square 2 = y

⇒ 4y = 40

⇒ y = 10 cm

⇒ Area = (10)^{2}

⇒ 100 cm^{2}

Area of third square = area of square 1 and 2

⇒ Area = 144 - 100

⇒ 44 cm2

Side of third square = √ 44

⇒ Perimeter = 4a

⇒ 4√ 44 cm

**⇒ 8√ 11 cm**