A_________________.B ABCD rectangle
| | BC/AB=3/5
| | A ABCD=375 m²
|_________________| ---------------------------------------
D C P ABCD=??
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BC/AB=3/5⇒BC=3AB/5
A=AB·BC
AB·3AB/5=375
3AB²/5=375
3AB²=1825
AB²=625
AB=25 m
BC=375:25
BC=15 m
P ABCD=2(AB+BC)
P ABCD=2(25+15)
P ABCD=2·40
P ABCD=80 m