diketahui lingkaran dengan jari-jari 28 cm.sudut AOB=60° dan sudut AOB: sudut COD=2:3,maka jumlah panjang busur AB dan busur CD adalah

Diket:
Jari-jari (r) = 28 cm
∠AOB = 60°
[tex] \frac{AOB}{COD} [/tex] = [tex] \frac{2}{3} [/tex]

Ditanya: ∠AB dan ∠CD = ?

Jawab:
K = 2 x π x r
K = 2 x [tex] \frac{22}{7} [/tex] x 28
K = 176 cm.

Kita cari ∠CD dulu.

[tex] \frac{60°}{COD} [/tex] = [tex] \frac{2}{3} [/tex]
∠COD x 2 = 60 x 3
∠COD = [tex] \frac{180}{2} [/tex]
∠COD = 90°

[tex] \frac{176}{CD} [/tex] = [tex] \frac{360}{90} [/tex]

[tex] \frac{176}{CD} [/tex] = [tex] \frac{4}{1} [/tex]
∠CD = [tex] \frac{176}{4} [/tex]
∠CD = 44.

Lalu cari ∠AB
[tex] \frac{K}{AB} [/tex] = [tex] \frac{360}{60} [/tex]

[tex] \frac{176}{AB} [/tex] = [tex] \frac{360°}{60°} [/tex]

[tex] \frac{176}{AB} [/tex] = [tex] \frac{6°}{1} [/tex]
∠AB = [tex] \frac{176}{6} [/tex] cm
atau ∠AB = 29,33 cm.