A rectangular square, Beibei and Lili.

Meeting at the top of point B means that Lili has lost 20 meters and Beibei has lost 20 meters. Beibei walked 40 meters more than Lily. 20+20 = 40 (meters).

Beibei walks 65438+100m50-40 =10 (m) more than Lili every minute.

Explain that the walking time is 4 minutes. 40÷ 10=4 (minutes).

Circumference: (40+50)×4=360 (m)

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Because there is no map. The answer may be wrong. It can be deduced by formula.