Given: ABC is an equilateral triangle. P, Q, R are points on AB, BC, CA respectively, such that
AP=BQ=CR
We know, AB=BC=CA
AP=BQ=CR
AB−AP=BC−BQ=CA−CR
BP=CQ=AR (I)
Now, In △APR and △PBQ
∠A=∠B=60∘
AP=BQ (Given)
BP=AR (From I)
Thus, △APR≅△BQP (SAS rule)
Hence, PQ=PR (By cpct)...(II)
Similarly, △APR≅△CRQ
hence, PR=QR ..(III)
thus, from II and III
PQ=QR=PR
∴△PQR is an equilateral triangle.