A directed line segment \( A B \) with \( A ( 1,3 ) \) and \( B ( 8,4 ) \) is partitioned by point \( C \) such that \( A C \) and \( C B \) form a \( 4 : 1 \) ratio. Find \( C \) .
- Write your answer as a coordinate point.
- Do not include spaces in your answer.
- Round to the nearest tenth if needed.