Point K lies on the segment MN, with MK = 5cm 3mm, KN = 3cm 8mm. Find the length of the line segment MN.

If a point lies on a segment, it means that it divides a certain segment into two parts, that is, into two segments.

If the entire segment is MN, then the point K divides it into segments MK and KN.

If it is known that MK is 5 cm 3 mm and KN is 3 cm 8 mm, then their sum will be equal to the segment MN.

Let us find it by the addition action.

5 cm 3 mm + 3 cm 8 mm = (5 cm + 3 cm) + (3 mm + 8 mm) = 8 cm + 11 mm = 9 cm 1 mm, since 1 cm = 10 mm.

Answer: the length of the segment MN is equal to the sum of the lengths of the segments MK and KN and equals 9 cm 1 mm.