Question

Tolong ya no. 9
pke cara ok...!!!

Answer 1

N = 6
a  = 12 cm
U6 = 47 cm

Un = a + (n-1)b
U6 = a + (6-1)b
= a + 5b

a + 5b = 47
12 + 5b = 47
5b = 47 - 12
5b = 35
b = 35 / 5
b = 7

Sn = 1/2 n (2a + (n-1)b)
S6 = 1/2 . 6(2.12 + (6-1)7)
= 3 (24 + (5)(7))
= 3 (24 + 35)
= 3 (59)
= 177 cm