The perimeter of a rhombus is 100 cm and one diagonal is 40 cm. Then the area of the rhombus

Concept use:

Perimeter of Rhombus Formula = 4 × a, where 'a' is the side.

Area of a Rhombus Formula = 1/2 × d₁ × d₂ where, d₁ and d₂ are the diagonals

Calculation:

Perimeter of Rhombus: 4 × a = 100, a = 25

a² = (d₁/2)² + (d₂/2)²

625 = (40/2)² + (d2/2)2

625 - 400 = (d2/2)2

d₂² = 4(225) = 900

d₂ = 30cm 

Area of a Rhombus = 1/2 × d1 × d2 = 1/2 × 40 × 30 = 600 cm square.

Hence, The Area of Rhombus is 600 cm square.