diketahui

Bab Lingkaran
Matematika SMP Kelas VIII

∠P + ∠R = 180°
∠P = 180° - 75°
∠P = 105°

∠O = 2 . ∠R
∠O = 2 . 75°
∠O = 150°

3x + 105° + 150° + 2x = 360°
5x = 360° - 255°
x = 105°/5
x = 21°

jawabannya B

< SOQ (1) = 2 × < SRQ = 2 × 75° = 150°
< SOQ (2) = 360° - 150° = 210°
< SPQ = 1/2 × < SOQ (2) = 1/2 × 210° = 105°
< SPQ + < PQO + < SOQ (1) + < PSO = 360°
105° + 2x° + 150° + 3x° = 360°
5x° + 255° = 360°
5x° = 360° - 255°
5x° = 105°
x = 105°/5
x = 21°
Jadi nilai x adalah 21° (b)