Complementary and supplementary angles

These are angle pairs defined by the total they add up to. The tool can derive them from your measured angle so you can copy/export them quickly.

Definitions

Complementary (sum to 90°)
Two angles are complementary if they add up to 90°.
Supplementary (sum to 180°)
Two angles are supplementary if they add up to 180°.

These relationships describe a sum. You may measure just one angle and compute the other if you know they form a right angle (90°) or a straight line (180°).

In the tool

  1. Place a measurement point and read the main angle value (degrees).
  2. Use the derived values (complementary/supplementary) shown alongside the point to verify constraints in diagrams.
  3. Export the data to reuse those values in a spreadsheet or report.

Exporting these values

In CSV/Excel/JSON exports, complementary and supplementary are included per point so you don’t need to recompute them later.

Related

Complementary vs Supplementary Angles (90° and 180°) | Smart Protractor