For a geometric sequence $\left\{ a _ { n } \right\}$ with positive common ratio, if $a _ { 1 } = 3 , a _ { 5 } = 48$, what is the value of $a _ { 3 }$? [3 points] (1) 18 (2) 16 (3) 14 (4) 12 (5) 10
For a geometric sequence $\left\{ a _ { n } \right\}$ with positive common ratio, if $a _ { 1 } = 3 , a _ { 5 } = 48$, what is the value of $a _ { 3 }$? [3 points]\\
(1) 18\\
(2) 16\\
(3) 14\\
(4) 12\\
(5) 10