Points M.N and R are collinear, MN = 11cm, RN = 20cm. Find the distance MR.

In order to find the distance MR, we must consider at least two possible solutions.

But first of all, let’s consider what is given to us in the condition. It is known that the points M, N and R are collinear. We are also given the lengths of the segments: MN = 11 cm, RN = 20 cm.

The length of the MR depends on the location of the point M.

First option:

Suppose that point M lies outside the segment NR, then the distance

MR = MN + NR, substitute the values ​​and calculate:

MR = 11 + 20 = 31 cm.

Second option:

Suppose that point M lies between N and R, then the distance

MR = NR – MN = 20 – 11 = 9 cm.

Since R cannot be located between M and N, since MN <NR.