A student used a vernier caliper to measure the diameter of a wooden cylinder. The diagram shows an enlargement of the caliper scales. What reading was recorded?

The reading recorded on the vernier caliper is 1.64 cm. This can be determined by aligning the zero mark on the vernier scale with the closest mark on the main scale, which is 1.6 cm. Then, counting the number of divisions on the vernier scale that align with the divisions on the main scale, we find that the 4th division on the vernier scale aligns with a division on the main scale. Each division on the vernier scale represents 0.01 cm, so adding 0.04 cm to the main scale reading of 1.6 cm gives a total reading of 1.64 cm.