Odpowiedzi

2009-12-17T17:20:23+01:00
A)p=pi*r^2=81 pi /:pi
r^2=81
r=9
ob=2pi *r=2pi*9=18pi mm
b)p=pi*r^2=49/100pi /:pi
r^2=49/100
r=7/10
ob=2pi*r=1,4pi cm
c) p=pi*r^2=36pi /:pi
r^2=36
r=6
ob=2pi*r=2pi*6=12pi km
2 3 2
2009-12-17T17:21:09+01:00
Obwód : 2πr
Pole : πr²

a)
πr² = 81π
r² = 81
r = √81
r = 9 mm

2πr = 2π9 = 18π = 18 × 3,14 = 56,52 mm

b)
πr² = 0,49π
r² = 0,49
r = √0,49
r = 0,7 cm

2πr = 2π0,7 = 1,4π = 1,4 × 3,14 = 4,396 cm

c)
πr² = 36π
r² = 36
r = √36
r = 6 km

2πr = 2π6 = 12π = 12 × 3,14 = 37,68 km
2 3 2
2009-12-17T17:23:35+01:00
P=81
r=9
L=2pi r
l=18pi mm
p=0,49
r=o,7
L=1,4pi cm
p=36
r=6
L=2pi r
L=12pi km
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