Question

tolong² besok dikumpulin

btw coret² tan jangan diurusin ya!​

Answer 1

Sudut Pusat & Sudut Keliling

Diketahui:

O pusat lingkaran

∠COB = 120°

∠ACB = 80°

Penyelesaian:

Sudut 1 lingkaran penuh 360°.

Jumlah sudut pada segitiga 180°.

ΔACO, ΔABO, dan ΔBCO semuanya segitiga sama kaki.

Sudut pusat = 2 × Sudut keliling

∠BOA = 2 × ∠ACB

∠BOA = 2 × 80°

∠BOA = 160°

∠BOA + ∠AOC + ∠COB = 360°

160° + ∠AOC + 120° = 360°

∠AOC = 360° - 280°

∠AOC = 80°

∠OAC + ∠OCA + ∠AOC = 180°

(∠OAC × 2) + 80° = 180°

∠OAC × 2 = 180° - 80°

∠OAC = 100°/2

∠OAC = 50°

∠OCB + ∠COB + ∠OBC = 180°

(∠OCB × 2) + 120° = 180°

∠OCB × 2 = 180° - 120°

∠OCB = 60°/2

∠OCB = 30°

∠ABO + ∠BAO + ∠BOA = 180°

(∠ABO × 2) + 160° = 180°

∠ABO × 2 = 180° - 160°

∠ABO = 10°

∠BAO = 10°

∠BAC = ∠OAC + ∠BAO

∠BAC = 50° + 10°

∠BAC = 60°

Maka:

a. ∠OAC = 50°

b. ∠BOA = 160°

c. ∠BAC = 60°

d. ∠AOC = 80°

e. ∠OCB = 30°

f. ∠ABO = 10°

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