Odpowiedź:
Obliczam promień bombki
P_p=\pi r^2P
p
=πr
2
\pi r^2=25\pi\ /:\piπr
2
=25π /:π
r^2=25r
2
=25
r= \sqrt{25}r=
25
r=5cmr=5cm
Obliczam pole powierzchni bombki
P_k=4\pi r^2P
k
=4πr
2
P_k=4 \cdot 5^2\piP
k
=4⋅5
2
π
P_k=4 \cdot 25\piP
k
=4⋅25π
P_k=100\piP
k
=100π
P_k \approx 100 \cdot 3,1P
k
≈100⋅3,1
P_k \approx 310cm^2P
k
≈310cm
2
Obliczam pole 20 bombek
P=20P_kP=20P
k
P=20 \cdot 310P=20⋅310
P=6200cm^2P=6200cm
2
P=62dm^2P=62dm
2
Obliczam ilość torebek
62:1=6262:1=62
