48 Diametri 14 cm bo'lgan doira yuzini toping.

Doira yuzining formulasi:

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

Shuningdek, radius diametrning yarimiga teng: \( r = \frac{d}{2} \). Shuning uchun yuz formulasi diametr orqali quyidagicha yozilishi mumkin:

\( A = \pi \left(\frac{d}{2}\right)^2 = \frac{\pi d^2}{4} \),

bu yerda \( A \) — doira yuzi, \( \pi \) — son, \( d \) — diametr.

Berilgan:

• Diametr \( d = 14 \) sm.

Hisoblash:

\( A = \frac{\pi (14 \text{ sm})^2}{4} \)

\( A = \frac{\pi \cdot 196 \text{ sm}^2}{4} \)

\( A = 49\pi \text{ sm}^2 \)

Ответ: Doira yuzi \( 49\pi \text{ sm}^2 \).