We are shown three pictures and asked to identify which one of them is not like others.
Let us find the ratio of width and length of each inscribed cricle.
Picture L:
Width = 3 units
Length = 4 units
Ratio = 3/4 = 0.75
Picture M:
Width = 4 units
Length = 8 units
Ratio = 4/8 = 0.50
Picture N:
Width = 9 units
Length = 12 units
Ratio = 9/12 = 0.75
As you can see, picture L and N has the same ratio of width and length that is 0.75 but the picture M has a different ratio of width and length that is 0.50
Therefore, we can conclude that picture M is not like others.