SSC CPO 2020 PYQ — Question 118

The correct answer is option 3 i.e. 10%

The area of the square decreased by 19% = $\dfrac{19}{100}$

Initial area of the square a₁²= 100

Side of the square a₁ = 10

Diagonal of the square = a₁$\sqrt{2}$ = 10$\sqrt{2}$

New area of the square a₂² = 81

Side of the square a₂ = 9

Diagonal of the square =   a₂$\sqrt{2}$ = 9$\sqrt{2}$

Percentage change in diagonal =  $\dfrac{10\sqrt{2}-9\sqrt{2}}{10\sqrt{2}}\times100$ = 10%