On a protractor, which line serves as the starting reference for measurement?

On a protractor, which line serves as the starting reference for measurement?

• A. Zero line
• B. Baseline
• C. Origin
• D. Base line

Answer: (D)

Baseline is the starting reference for measurement because it is the straight reference line you align with one side of the angle. When you place this line along a ray, the measurement begins from 0 degrees along that baseline, and you read the number where the other ray crosses the curved edge of the protractor. This fixed line provides a consistent starting point for all angle measurements, which is why baseline is the best term to describe the starting reference.

Baseline is the starting reference for measurement because it is the straight reference line you align with one side of the angle. When you place this line along a ray, the measurement begins from 0 degrees along that baseline, and you read the number where the other ray crosses the curved edge of the protractor. This fixed line provides a consistent starting point for all angle measurements, which is why baseline is the best term to describe the starting reference.