47 Radiusi 12 cm bo'lgan doira yuzini toping.

Doira yuzining formulasi:

\( A = \pi r^2 \),

bu yerda \( A \) — doira yuzi, \( \pi \) — son, \( r \) — radius.

Berilgan:

• Radius \( r = 12 \) sm.

Hisoblash:

\( A = \pi \cdot (12 \text{ sm})^2 \)

\( A = \pi \cdot 144 \text{ sm}^2 \)

\( A = 144\pi \text{ sm}^2 \)

Ответ: Doira yuzi \( 144\pi \text{ sm}^2 \).