Question

If the area of a rhombus is 100 cm2, and one diagonal is double the other, then what is the length of the larger diagonal?

• A. 5
• B. 10
• C. 20
• D. 40

Answer 1

The correct option is C 20

Area of rhombus = $\frac{1}{2}\times d_1\times d_2$.
Let the smaller diagonal be a, then larger diagonal = 2a .
Given : Area of rhombus = 200 cm2
$\frac{1}{2}\times a\times 2a=100a^2=100a=\sqrt{100}=10$
Therefore, the larger diagonal = 2x = 2(10) = 20 cm.