Draw a linear pair of angles. Bisect each of the two angles. Verify that the two bisector rays are perpendicular to each other.
Steps of construction :
(i) Draw a linear pair ∠DCA and ∠DCB.
(ii) Draw the bisector of ∠DCA and ∠DCB. Now, ∠ECF is equal to 90∘.
Verification : ∵∠DCA+∠DCB=180∘
⇒ 12∠DCA+12DCB=180∘×12=90∘
∠ECF=90∘
i.e. EC and FC are perpendicular to each other.