Find the missing term in given series? 4, 6, 9, $13\frac{1}{2}$, ?

$22\frac{3}{4}$ $20\frac{1}{4}$ 19 $17\frac{1}{2}$

$20\frac{1}{4}$

4, 6, 9, $13\frac{1}{2}$, ? The logic followed is = Previous term × 1.5 So, the next term will be = $13\frac{1}{2}$ × 1.5 = $20\frac{1}{4}$