Odpowiedź :
Nie jestem pewna, ale wg mnie tak:
30°/360°×πr²=1/9π
1/12×πr²=1/9π /:π
1/12r²=1/9 /×12
r²=12/9 /√
r=√4/3
30°/360°×πr²=1/9π
1/12×πr²=1/9π /:π
1/12r²=1/9 /×12
r²=12/9 /√
r=√4/3
30 stopni =pi?6
P/( pi*r^2) = (pi/6)/(2pi) =1/12
[(1/9)*pi]/(pi*r^2) = (1/9)/(r^2) = 1/12
9*r^2 =12
r^2 =12/9 =(4*3)/9
r =[2*pierw. kw. z 3]/3
P/( pi*r^2) = (pi/6)/(2pi) =1/12
[(1/9)*pi]/(pi*r^2) = (1/9)/(r^2) = 1/12
9*r^2 =12
r^2 =12/9 =(4*3)/9
r =[2*pierw. kw. z 3]/3