Odpowiedzi

2009-11-09T17:35:00+01:00
P<w> = 1/9π
α = 135°

p<w> = α/360° × πr²

1/9π =135°/360° × πr² | ÷9

1/9π=3/8 × πr²

8/27 ×π= πr²

√(8 π/27π)= r

r =2/3√2/3