Points M, K and N lie on one straight line, find the length of the segment KN, if MK is 15cm, MN is 6cm.

Option 1

If point M and K are the end points of the line segment, then point N lies between these points. To find the length of the segment KN, it is necessary to subtract the length of the segment MN from the length of the MK segment:

MK – MN = KN;

KN = 15 – 6 = 9 (cm) – the length of the segment KN;

Option 2

If points K and N are the end points of the segment, then point M is located between them. In order to find the length of the segment KN, it is necessary to add the lengths of the segments MK and MN:

MK + MN = KN;

KN = 15 + 6 = 21 (cm) – length of the segment KN

Answer: 21 cm section length KN.