🔍 Key Concepts

• Main scale vs. vernier scale – how to get the whole inches and tenths from the main scale and the thousandths from the vernier scale • How a vernier alignment works – the line on the vernier that exactly lines up with a line on the main scale gives the extra digits • Converting the reading 4.340 inches into what you should see on each scale (4 inches + 0.3 + 0.040)

💭 Think About

• First, decide where the zero on the vernier lies on the main scale: is it just past 4 inches, or between 3 and 4 inches? That tells you which figures you can eliminate immediately. • Next, look for which figure shows a vernier line that lines up exactly with a main‑scale line at about 0.040 past the nearest tenth mark. • Compare how many vernier divisions equal 0.040 inches on this style of caliper: what does each small vernier division represent in thousandths of an inch?

✅ Before You Answer

• Be sure the figure you choose shows the zero of the vernier slightly to the right of the 4‑inch mark on the main scale (not at 3.x or 4.5, etc.). • Verify that the tenths (0.3) are correctly shown on the main scale before you worry about the thousandths. • Confirm that exactly one vernier line is in perfect alignment with a main‑scale line and that this corresponds to 0.040 inch beyond the main‑scale reading.