a)
Ppatrat=4×l⇔
⇔Ppatrat=4×3⇔
⇔Ppatrat=12 cm
b)
Ppatrat=4×l⇔
⇔Ppatrat=4×7⇔
⇔Ppatrat=28 cm
c)
Ppatrat=4×l⇔
⇔Ppatrat=4×8⇔
⇔Ppatrat=32 cm
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a)
Pdreptunghi=2×L+2×l⇔
⇔Pdreptunghi=2×6+2×2⇔
⇔Pdreptunghi=12+4⇔
⇔Pdreptunghi=16 cm
b)
Pdreptunghi=2×L+2×l⇔
⇔Pdreptunghi=2×8+2×5⇔
⇔Pdreptunghi=16+10⇔
⇔Pdreptunghi=26 cm