Răspuns :
[tex] P_{dreptunghi} [/tex] = 2(L+l) =40 <=> 2(16+l)=40 => 16+l=20 =>l=4 (cm).
[tex] A_{dreptunghi} [/tex] = L*l=4*16=64 (cm²).
[tex] A_{patrat} = A_{dreptunghi} [/tex] => [tex] A_{patrat} =[/tex] 64 cm².
[tex] A_{patrat} = l_{patrat} ^{2} [/tex] <=> 64= [tex] l_{patrat} ^{2} [/tex] => [tex] l_{patrat} =8 cm[/tex]
[tex] A_{dreptunghi} [/tex] = L*l=4*16=64 (cm²).
[tex] A_{patrat} = A_{dreptunghi} [/tex] => [tex] A_{patrat} =[/tex] 64 cm².
[tex] A_{patrat} = l_{patrat} ^{2} [/tex] <=> 64= [tex] l_{patrat} ^{2} [/tex] => [tex] l_{patrat} =8 cm[/tex]
p dreptunghi= 2xL+2xl
p patrat=4xl
2L+2l=40
2x16+2xl=40
32+2xl=40
2xl=40-32
2xl=8
l=8:2
l=4 latimea dreptunghi
a dreptunghi=Lxl
a patrat=l²
Lxl=l²
16x4=l²
64=l²
l=√64=8 latura patrat
p patrat=4xl
2L+2l=40
2x16+2xl=40
32+2xl=40
2xl=40-32
2xl=8
l=8:2
l=4 latimea dreptunghi
a dreptunghi=Lxl
a patrat=l²
Lxl=l²
16x4=l²
64=l²
l=√64=8 latura patrat