Practice | Hashtable

Home > Practice > Arithmetic Aptitude > Area > Miscellaneous

1. The diagonal of a rectangle is $\sqrt{41}$ cm and its area is 20 sq. cm. The perimeter of the rectangle must be:

A. 9 cm

B. 18 cm

C. 20 cm

D. 41 cm

Solution:

\begin{aligned} \sqrt{l^{2} + b^{2}} = \sqrt{41} \\ Also, l b = 20 \\ {(l + b)}^{2} = (l^{2} + b^{2}) + 2 / b = 41 + 40 = 81 \\ \Rightarrow (l + b) = 9 \\ ∴ Perimeter = 2 (l + b) = 18 c m \end{aligned}

You must login to add comments. Login now.