Consider the geometric sequence 16/9, 4, 9, ... What is the eighth term of the sequence? Express your answer as a common fraction.

Use the formula a_n = a_1 r^n-1

a_n = (16 * 9^n-2)/(4^n-1) (common ratio)

a_8=(16*9^6)/(4^7)

a_8 = ?