Pada gambar disamping diketahui panjang OP =28 cm dan PQ =17,6 cm .Hitunglah luas juring POQ
Takamori37
OP = 28 cm (Jari-jari) PQ = 17,6 cm (Busur) Maka, PQ = a/360° x 2 x 22/7 x 28 17,6 = a/360° x 44 x 4 17,6 = 176 x a/360° a/360° = 17,6/176 a/360° = 1/10 a = 36°
Sehingga, luas juring: Lj = a/360° x 22/7 x OP² Lj = 36°/360° x 22/7 x 28² Lj = 1/10 x 22/7 x 28 x 28 Lj = 1/10 x 22 x 4 x 28 Lj = 1/10 x 2.464 Lj = 246,4 cm²
PQ = 17,6 cm (Busur)
Maka,
PQ = a/360° x 2 x 22/7 x 28
17,6 = a/360° x 44 x 4
17,6 = 176 x a/360°
a/360° = 17,6/176
a/360° = 1/10
a = 36°
Sehingga, luas juring:
Lj = a/360° x 22/7 x OP²
Lj = 36°/360° x 22/7 x 28²
Lj = 1/10 x 22/7 x 28 x 28
Lj = 1/10 x 22 x 4 x 28
Lj = 1/10 x 2.464
Lj = 246,4 cm²