Question

Each side of a square is 5 cm. The perimeter of the equilateral triangle formed on the diagonal of the square would be-

• A. $15cm$
• B. $20cm$
• C. $20\sqrt{2}cm$
• D. $15\sqrt{2}cm$

Answer 1

The correct option is D $15\sqrt{2}cm$

Side of the square = $5cm$
So, the diagonal of the square is $d=\sqrt{9^2+5^2}=5\sqrt{2}$
Hence, the perimeter is $p=3d$
$p=3\times 5\sqrt{3}=15\sqrt{2}cm$