Question

1.Calculati aria unui dreptunghi cu lungimea cu 7 cm mai mare decat latimea si perimetrul de 82 cm.

2. Aflati masurile unghiurilor unui patrulater in cazul in care sunt direct proportionale cu numele 9 ; 7 ; 13 si 11

Answer 1

P = 82 = 2L + 2l 
82 = 2(l+7) + 2l
82 = 4l + 14
4l = 68
l = 17 cm
L= 24 cm
A =17*24 = 408 cm^2

A/9=B/7=C/13=D/11=K
A=9k, B=7k, C=13k, D=11k

A+B+C+D=360°
9K+7K+13K+11K=360
40K=360
K=9
A=9*9=
B=7*9=
C=13*9=
D=11*9=

Answer 2

1)L=l+7
P/2=p=semiperimetrul=L+l=41
l+7+l=41
2l=34
l=17cm
L=17+7=24cm
L×l=A
A=24×17
A=408cm^2
2)m<A/9=m<B/7=m<C/13=m<D/11=k
m<A=9k
m<B=7k
m<C=13k
m<D=11k
m<A+m<B+m<C+m<D=360°
9k+7k+13k+11k=360
40k=360
k=9
m<A=81°
m<B=63°
m<C=117°
m<D=99°