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**How to justify construction of 90 degrees angle**

**For justifying construction of 90 degrees angle first follow all the steps.**

**The below given steps will be followed to construct an angle of 90°.**(i) Take the given ray PQ. Draw an arc of some radius taking point P as its centre, which intersects PQ at R.(ii) Taking R as centre and with the same radius as before, draw an arc intersecting the previously drawn arc at S.(iii) Taking S as centre and with the same radius as before, draw an arc intersecting the arc at T (see figure).(iv) Taking S and T as centre, draw an arc of same radius to intersect each other at U.(v) Join PU, which is the required ray making 90° with the given ray PQ.

**JUSTIFICATION :-**

You can justify it by proving

**∠UPQ = 90°**. For that join

**PS**and

**PT.**

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