Tentukan suku ke 10 dan jumlah 5 suku pertama dari barisan geometri 175 , 35 , 7

U10 = 175 x (35/175)^9 = 175 x (1/5)^9 = 175/1.953.125 = 7/78.125

S5 = 175 x (1 - 1/5^5)/(1 - 1/5)
= 175 ÷ 4/5 x (3.125-1)/3.125
= 175 x 5/4 x 3.120/3.125
= 175 x 780/625
= 7x780/25
= 218,4