$$\bbox[yellow, 5px, border: 2px solid red] {\text{Luas Juring AOB} = \dfrac{\theta}{360^{\circ}} \times \pi \cdot r^2}$$
$$\bbox[yellow, 5px, border: 2px solid red] {\text{Luas Juring AOB} = \dfrac{1}{2}\cdot \theta \cdot r^2}$$
Jawaban: A
\(\text{Luas Juring AOB} = \dfrac{\theta}{360^{\circ}} \times \pi \cdot r^2\)
\(\text{Luas Juring AOB} = \dfrac{60^{\circ}}{360^{\circ}} \times \dfrac{22}{7} \cdot 14^2\)
\(\text{Luas Juring AOB} = \dfrac{1}{6} \times \dfrac{22}{\cancel{7}} \cdot \cancelto{2}{14} \cdot 14\)
\(\text{Luas Juring AOB} = 102,67 \text{ cm}^2\)
Jawaban: C
\(\dfrac{\text{Luas Juring AOB}}{\text{Luas Juring COD}} = \dfrac{\dfrac{30^{\circ}}{360^{\circ}} \times \pi \cdot r^2}{\dfrac{150^{\circ}}{360^{\circ}} \times \pi \cdot r^2}\)
\(\dfrac{\text{Luas Juring AOB}}{\text{Luas Juring COD}} = \dfrac{\dfrac{30^{\circ}}{\cancel{360^{\circ}}} \times \cancel{\pi \cdot r^2}}{\dfrac{150^{\circ}}{\cancel{360^{\circ}}} \times \cancel{\pi \cdot r^2}}\)
\(\dfrac{44}{\text{Luas Juring COD}} = \dfrac{30^{\circ}}{150^{\circ}}\)
\(\dfrac{44}{\text{Luas Juring COD}} = \dfrac{1}{5}\)
Kali silang
\(\text{Luas Juring COD} = 5 \times 44\)
\(\text{Luas Juring COD} = 220 \text{ cm}^2\)
Diketahui luas juring AOB suatu lingkaran yang berdiameter 24 cm adalah \(\dfrac{396}{7}\). Sudut pusat AOB pada lingkaran tersebut adalah…
Jawaban: B
\(\text{Luas Juring AOB} = \dfrac{\theta}{360^{\circ}} \times \pi \cdot r^2\)
\(\dfrac{396}{7} = \dfrac{\theta}{360^{\circ}} \times \dfrac{22}{7} \cdot 12 \cdot 12\)
\(\dfrac{396}{\cancel{7}} = \dfrac{\theta}{360^{\circ}} \times \dfrac{22}{\cancel{7}} \cdot 12 \cdot 12\)
\(396= \dfrac{\theta}{360^{\circ}} \times 3168\)
\(\dfrac{396}{3168}= \dfrac{\theta}{360^{\circ}}\)
\(\dfrac{1}{8}= \dfrac{\theta}{360^{\circ}}\)
Kali silang
\(\theta = \dfrac{1}{8} \times 360^{\circ}\)
\(\theta = 45^{\circ}\)
