Uzupełniamy tabelkę.

$d_1$	$8dm$	$25cm$	$18cm$	$14cm$	$3,4dm$	$51,8cm$
$d_2$	$5dm$	$4\frac{1}{2}dm$	$36cm$	$14cm$	$6\frac{1}{2}dm$	$26cm$
$P=\frac{d_1\cdot d_2}{2}$	$20d{m}^2$	$562,5c{m}^2$	$324c{m}^2$	$98c{m}^2$	$1105c{m}^2$	$673,4c{m}^2$

 

Obliczenia:

$\frac{8\cdot 5}{2}=\frac{40}{2}=20$

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$4,5dm=45cm$

$\frac{25\cdot 45}{2}=\frac{1125}{2}=562,5$

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$\frac{18\cdot \square }{2}=324$   $/\cdot 2$

$18\cdot \square =648$   $/:18$

$\square =36$

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$\frac{14\cdot \square }{2}=98$ $/\cdot 2$

$14\cdot \square =196$ $/:14$

$\square =14$

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$6,5dm=65cm$

$\frac{65\cdot \square }{2}=1105$   $/\cdot 2$

$65\cdot \square =2210$ $/65$

$\square =34$

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$\frac{51,8\cdot \square }{2}=673,4$ $/\cdot 2$

$51,8\cdot \square =1346,8$ $/:51.8$

$\square =26$