Neka su
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i
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dva paralelna pravca. Kružnica
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dodiruje pravac
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u točki
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i siječe pravac
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u različitim točkama
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i
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. Neka je
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točka na pravcu
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i neka dužine
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i
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sijeku kraći luk
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redom u točkama
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i
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, različitima od
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i
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.
Dokaži da pravac
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prolazi polovištem dužine
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.
%V0
Neka su $p$ i $q$ dva paralelna pravca. Kružnica $k$ dodiruje pravac $p$ u točki $A$ i siječe pravac $q$ u različitim točkama $B$ i $C$. Neka je $T$ točka na pravcu $p$ i neka dužine $\overline{TB}$ i $\overline{TC}$ sijeku kraći luk $AC$ redom u točkama $K$ i $L$, različitima od $B$ i $C$.
Dokaži da pravac $KL$ prolazi polovištem dužine $\overline{AT}$.