Question

construct a square which each of the diagonal is 5 cm long​

Answer 1

draw a line segment AC = 5 cm length

now draw perpendicular bisector of AC

let it intersect AC at point O.

with O as centre and radius equal to half of the length of the diagonal (2.5 cm) draw two arcs on either side of AC on the perpendicular bisector.

mark the point of intersections of the arcs and perpendicular bisector as B and C.

join points A,B; points B,C; points C,D ; points A,D .

thus ABCD is the required square with length of diagonal 5 cm.