Question

problema 7 dau coroana

Answer 1

Ca sa fie patrat, lungimea=latimea, adica :
L-40=l-10 =>L-l=30 =>L=l+30
Stim ca perimetrul 2L+2l=450 sau L+l=225
=>l+30+l=225 =>2l=195 =>l=97,5 m si L=127,5 m
Aria=L·l=12431,25 m²
1 ar=100 m² 
100 m² _________ 100 kg
12431,25 m² _____ x
x=12431,25 kg

Answer 2

L+l=P:2=450:2=225
L-40=l-10


L+l=225
L-l=30
adunand ecuatiile , obtinem
2L=255⇒L=127,5m=12,75dam
l=L-30=127,5-30 =97,5m=9,75dam

S=12,75 dam*9,75 dam=124,3125 dam²=124,3125 ari

1 ar....100kg struguri
124,3125ari......x kg struguri
 marimi direct proportionale (cu cat avem o suprafata cultivata mai mare , cu atata avem mai multi struguri)
x=124,3125*100=12431,25kg=12,43125t