Defined distances

Mark writes four points on a line at different lengths. What is the distance between the two points furthest apart?

Problem



Mark marked out the points $J$, $K$, $L$ and $M$ on a straight line, so that

$JK=13$cm

$KL=11$cm

$LM=14$cm

$MJ=12$cm



What is the distance, in cm, between the two points furthest apart?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.