Cambridge Secondary (7-9). Stage 7. MCE Science. Student Book - Unit 2: Measurements - Question 94

Han measures the height of two different books using a rule. He presents his results in the table below.

| | Measurement 1 in cm | Measurement 2 in cm | Measurement 3 in cm |
|---|---|---|---|
| Book 1 | 20.8 | 20.9 | 20.7 |
| Book 2 | 8.6 | 21.4 | 8.7 |

How could Han make these measurements more reliable?