tolong yah pakai cara,sudah capek aku cari jawabannya ,please....

U5/U3 = 6/24
ar^4/ar^2 = 1/4
r^2 = 1/4
r = ✓1/4
r = 1/2

U3 = ar^2
24 = a x 1/4
a = 24 x 4 =96

S6 = (96(1 - (1/2)^6))/(1 - 1/2)
=21