Ma poate ajuta cineva?

Răspuns:
Răspuns:
[tex]L=36=>Aria=L^2=36^2=1290m^2[/tex]
[tex]30g/m^2-rata[/tex]
[tex]10kg =[/tex]$[tex]15.80[/tex]
In total va folosi: [tex]30*1296=38880g=38.8kg[/tex](de fertiliser)
10kg......$15.80
38.8kg.......$x
=> x=[tex]\frac{38.8*15.8}{10}=61.304[/tex]$
Acum vom calcula cat va costa ptr. cele 3 semicercuri:
Deoarece latura patratului reprezinta diametrul care este egal cu 36m =>
raza = 18m
Aria unui semicerc este [tex]\frac{\pi r^2}{2}[/tex], iar a celor 3 semicercuri este [tex]3*\frac{\pi r^2}{2}[/tex]
Aria = [tex]3*\frac{\pi *18^2}{2}= \frac{3\pi *324}{2}=3\pi *162=1526.8m^2[/tex]
In total va folosi: [tex]30*1562.8=46884g=46.884kg[/tex]
10kg.....$15.80
46.884kg....$x
=>x=[tex]\frac{15.80*46.884}{10}= 74.07[/tex]$
Tot suma va fi = 74.07$+61.3$=134.37$
The surface of the lawn is:
[tex]\it S=3\cdot\dfrac{\pi R^2}{2}+\ell^2=3\cdot\dfrac{\pi\cdot18^2}{2}+36^2=3\cdot\dfrac{\pi\cdot18^2}{2}+18^2\cdot2^2=\\ \\ \\ =18^2\Big(\dfrac{3\pi}{2}+4\Big)\approx324\cdot\Big(\dfrac{3\cdot3.14}{2}+4\Big)=324\cdot8.71 \approx\ 2822\ m^2[/tex]
Required fertiliser is:
[tex]\it 2822\cdot30=84660g=84.66kg[/tex]
But, the fertiliser is only sold in 10kg bags, so :
[tex]\it 84,66 kg \approx 90kg \Rightarrow 9\ \ bags[/tex]
The cost is:
9 · 15.80 = 142.20 £