Ini gimana caranya nomor 1 sampai 3

1][
r = 10,5 cm = 21/2 cm

Luas juring POQ
= 60°/360° × luas lingkaran
= 1/6 × πr²
= 1/6 × 22/7 × 21/2 × 21/2
= 1/6 × 11 × 3/2 × 21
= 1/2 × 1/2 × 11 × 21
= 232/4
= 58 cm²

Panjang busur PQ
= 60°/360° × keliling lingkaran
= 1/6 × 2πr
= 1/3 × 22/7 × 21/2
= 22/2
= 11 cm

2][
Lingkaran
Keliling = 88 cm

a. r = ... ?
k = 88
2πr = 88
2 × 22/7 × r = 88
r = 88 × 7 / 44
r = 2 × 7
r = 14 cm

b.
Panjang busur MN
= 45°/360° × keliling
= 1/8 × 88
= 11 cm

3][
luas AOB/luas COD = sudut AOB/sudut COD
50/175 = 40/COD
COD = 40 × 175/50
COD = 4 × 35°
COD = 140°