The length of the diagonal of a square is 20 cm then its perimetre ?A40√2 cmB40 cmC200 cmD10√2 cmAnswer: A. 40√2 cm Read Explanation: Let 'a' be the side of a square a√2 = 20 a=20/2√2 = 10√2 Perimeter of square = 4 x a = 4 x 10√2 =40√2 cm Read more in App