the.com/right triangle
A triangle with one angle so sure of itself, it's exactly 90 degrees.
means A triangle that has one 90-degree angle, with the side opposite that angle called the hypotenuse.
from 'Right' here doesn't mean correct — it comes from Latin 'rectus,' meaning straight or upright, the same root that gives us 'erect' and 'rectitude.' A right angle was originally the 'upright' angle, like a perfectly vertical post meeting flat ground, and 'triangle' simply comes from Latin 'tri-' (three) plus 'angulus' (angle/corner). So a right triangle is literally a three-cornered shape with one truly 'upright' corner.
- defining feature
- has one 90-degree angle, no exceptions
- famous theorem
- a squared plus b squared equals c squared
- longest side
- hypotenuse always faces the right angle
- secret weapon
- powers GPS, architecture, and trigonometry itself