According to the question:

Let us assume the heights (in cm) of ten students of our class be as follows:

125, 129, 130, 133, 134, 136, 138, 141, 144, 146

Now,

We can observe that,

Highest value among these observations = 146

Lowest value among these observations = 125

Now,

We have to find the range of the given data.

Hence,

Range = Highest value – Lowest value

= 146 – 125

= 21 cm