Геометрическая прогрессия

1)
$cn = c1 \times {q}^{n - 1} \\ c3 = c1 \times {q}^{2} \\ c1 = \frac{c3}{ {q}^{2} } = \frac{144}{16} = 9$
Ответ: 9.

2)
$cn = c1 \times {q}^{n - 1} \\ c2 = c1 \times q = 3 \times 3 = 9 \\ c3 = c1 \times {q}^{2} = 3 \times 9 = 27 \\ c4 = c1 \times {q}^{3} = 3 \times 27 = 81 \\ c5 = c1 \times {q}^{4} = 3 \times 81 = 243$
Ответ: 3; 9; 27; 81; 243