Question 1115344
{{{ S[n] = (a[1]*(1-r^n)) / (1-r) }}} ,   {{{ r <> 1 }}}

where 
{{{ n }}} = number of terms
{{{ a[1] }}} = first term
{{{ r }}} = common ratio <br>

Here,
{{{ n  = 9 }}}
{{{ a[1] = 1/4 }}}
and
{{{ r = 4 }}}
<br>

You can plug in the values to find  {{{ S[9] = 87381/4 = 21845.25 }}}