To mark X spot, the ribbon should be stretched diagonally from one end to another. Since the flag is a square, a diagonal cuts the square into 2 equal triangles. The diagonal length is the hypotenuse of the triangle, as the triangles formed are 2 right angled triangles. Using Pythogoras' theorem, hypotenuse can be found out with the following equation; H² = X² +X² where H is the hypotenuse in other words the diagonal X - length of the triangle, since its a square all lengths are equal X- 12 inches H² = 12² + 12² = 144+144 H² = 288 H = 16.9 inches≈17 inches to make the mark X he will need 2 strips of ribbons of length 17 inches each. total length of the ribbon needed = 34 inches
