tolong bantu jawab ya yg no 18 pliss butuh banget

panjang busur ab = 12,56cm
40/360 × π × d = 12,56cm
1/9 × 3,14 × d = 12,56cm
1/9d = 12,56cm : 3,14
1/9d = 4cm
d = 4cm × 9
d = 36cm

r = 18cm

luas juring oab = 40/360 × π × r × r
= 1/9 × 3,14 × 18cm × 18cm
= 3,14 × 18cm × 2cm
= 113,04cm²

jawabannya adalah c