Use the information given to identify the a_9 term of the geometric sequence: a_4=1/2, r=1/2

A given term in a PG = a₁rⁿ⁻¹

Let' calculate the 1st term a₁, knowing a term & the common factor/ratio

a₄ = 1/2 so 1/2 = a₁ (1/2) ³

1/2 = a₁/8 and a₁ = 4

Now calculate a₉ = a₁. r⁸

a₉ = 4. (1/2) ⁸ and a₉ = 1/64