We know that each angle of a square is a right angle (i.e., 90∘)
To construct a square of sides 3cm, use the following steps.
(i) Draw a line segment AB of length 3cm.
(ii) Now, construct an angle of 90∘ at points A and B of the line segment AB and plot the parallel lines AX and BY at these points.
(iii) Cut AD and BC of length 3cm on AX and BY, respectively.
(iv) Draw an angle of 90∘ at any one of the point C or D and join both points by a line segment CD of length 3cm.Thus, ABCD is the required square of side 3cm.
(Step iv can be skipped. Just join the points DC and if all the previous steps till step 3 are correct and precise, the ∠ADC and ∠BCD will automatically be 90∘ )