nomor 18 dan 19 tolong di bantu ya...

18. CD2 = 17^2 - (11-3)^2
CD2 = 289 - 8^2
CD^2 = 289 -64
CD^2 = 225
CD = √225 = 15 cm

B. 15 cm

19. 150° n = (n -2) x 180°
150°n = 180n - 360°
360° = 180n - 150°n
360° = 30 n
n = 360/30
n =12

b. 12