Ppatrat=3/5 din Pdreptunghi
Pd=2l+2L
ldreptunghi=2/3 din l patrat
Pd=64*2+2l=128+2l
Ppatrat=4l
4l=3/5 * (128+2l)
4l= (384+6l)/5
20l=384 +6l
20l=384 +6 * 2/3 * l
20l=384 +2*2l
20l=384+4l
20l-4l=384
16l=384
lpatrat=24
ldreptunghi=2/3 *24= 2*8=16
Pdreptunghi=128+2*16=128+32= 160