tolong bantu yah pake cara?9 sama 10

19.
L. layang = ((AB + AC) * AO)/2
48 = ((8 + 8) * AO))/2
48 = (16*AO)/2
48 = 8*AO
6 = AO

20.

p = 17
R = 12
r = 4
d = ?

d^2 = p^2 - (R - r)^2
= 17^2 - (12 - 4)^2
= 289 - (8)^2
= 289 - 64
= 208
d = 15

hope it helps