Electrical mathQuestion 480 of 1506

Why are the two non-right angles of a right triangle complementary?

  1. Together they must add to 180 degrees
  2. Together they must add to 90 degrees
  3. Each must equal 45 degrees
  4. Each must be greater than 90 degrees
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Correct answer: Together they must add to 90 degrees

The right angle uses 90 of the 180 degrees.

Source: Trigonometry and Single Phase AC Generation for Electricians (Flinn), 1.2: Triangles

Practice electrical math

Questions last reviewed: 18 October 2026