Question

Ma poate ajuta cineva?

Answer 1

Răspuns:

Răspuns:

$L=36=>Aria=L^2=36^2=1290m^2$

$30g/m^2-rata$

$10kg =$$$15.80$

In total va folosi: $30*1296=38880g=38.8kg$(de fertiliser)

10kg......$15.80

38.8kg.......$x

=> x=$\frac{38.8*15.8}{10}=61.304$$

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 $\frac{\pi r^2}{2}$, iar a celor 3 semicercuri este $3*\frac{\pi r^2}{2}$

Aria = $3*\frac{\pi *18^2}{2}= \frac{3\pi *324}{2}=3\pi *162=1526.8m^2$

In total va folosi: $30*1562.8=46884g=46.884kg$

10kg.....$15.80

46.884kg....$x

=>x=$\frac{15.80*46.884}{10}= 74.07$$

Tot suma va fi = 74.07$+61.3$=134.37$

Answer 2

The surface of the lawn is:

$\it S=3\cdot\dfrac{\pi R^2}{2}+\ell^2=3\cdot\dfrac{\pi\cdot18^2}{2}+36^2=3\cdot\dfrac{\pi\cdot18^2}{2}+18^2\cdot2^2=\\ \\ \\ =18^2\Big(\dfrac{3\pi}{2}+4\Big)\approx324\cdot\Big(\dfrac{3\cdot3.14}{2}+4\Big)=324\cdot8.71 \approx\ 2822\ m^2$

Required fertiliser is:

$\it 2822\cdot30=84660g=84.66kg$

But, the fertiliser is only sold in 10kg bags, so :

$\it 84,66 kg \approx 90kg \Rightarrow 9\ \ bags$

The cost is:

9 · 15.80 = 142.20 £