a)

$\text{a}=30\text{mm}$  

Pole kwadratu obliczamy ze wzoru:

$\text{P}={\text{a}}^2$  

$\text{P}={\left(30\text{mm}\right)}^2$  

$\text{P}=900{\text{mm}}^2$  

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b)

$\text{a}=15\text{cm}$  

Pole kwadratu obliczamy ze wzoru:

$\text{P}={\text{a}}^2$  

$\text{P}={\left(15\text{cm}\right)}^2$  

$\text{P}=225{\text{cm}}^2$  

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c)

$\text{a}=8\text{m}$  

Pole kwadratu obliczamy ze wzoru:

$\text{P}={\text{a}}^2$  

$\text{P}={\left(8\text{m}\right)}^2$  

$\text{P}=64{\text{m}}^2$  

---

d)

$\text{a}=50\text{dm}$  

Pole kwadratu obliczamy ze wzoru:

$\text{P}={\text{a}}^2$  

$\text{P}={\left(50\text{dm}\right)}^2$  

$\text{P}=2500{\text{dm}}^2$