Proportional Scales

How to use a Proportional Scale

Using a proportional scale involves a few simple steps to accurately resize an object while maintaining its proportions:

1. Determine the Original and Desired Scale Ratios: Identify the scale ratio of the original drawing or object (e.g., 1:1) and the desired scale ratio you want to convert it to (e.g., 1:2 for enlarging or 2:1 for reducing).
2. Set the Scale: Adjust the sliding scales on the proportional scale to match the original and desired ratios. Proportional scales typically have marked ratios or fractions that you can align.
3. Measure the Original Object: Use the original scale measurement on the proportional scale to measure the dimensions of the original object or drawing.
4. Read the Corresponding Measurement: Look at the corresponding measurement on the desired scale. The proportional scale will show you the new dimension that maintains the same proportion as the original.
5. Apply the Measurement: Use the new measurement to resize your object or drawing accordingly, ensuring all elements are adjusted proportionally.

Example:

If you have a drawing that is 10 cm long and you want to double its size:

1. Original Scale: 1:1 (the current size)
2. Desired Scale: 1:2 (the new size)
3. Set the Proportional Scale: Align the 1:1 ratio on the original scale with the 1:2 ratio on the desired scale.
4. Measure the Original Length: Place the 10 cm mark on the original scale.
5. Read the New Length: The corresponding mark on the desired scale should read 20 cm.

This tells you that the new length should be 20 cm to maintain the same proportion as the original 10 cm drawing.