Right Angle

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A Right Angle is an angle that is equal to [math]\displaystyle{ 90^o, \pi/2 }[/math] radians .



References

2015

  • (Wikipedia, 2015) ⇒ http://wikipedia.org/wiki/Angle#Types_of_angles
    • QUOTE:
      • Angles smaller than a right angle (less than 90°) are called acute angles ("acute" meaning "sharp").
      • An angle equal to 1/4 turn (90° or [math]\displaystyle{ \pi/2 }[/math] radians) is called a right angle. Two lines that form a right angle are said to be normal, orthogonal, or perpendicular.
      • Angles larger than a right angle and smaller than a straight angle (between 90° and 180°) are called obtuse angles ("obtuse" meaning "blunt").
      • An angle equal to 1/2 turn (180° or [math]\displaystyle{ \pi }[/math] radians) is called a straight angle.
      • Angles larger than a straight angle but less than 1 turn (between 180° and 360°) are called reflex angles.
      • An angle equal to 1 turn (360° or 2π radians) is called a full angle, complete angle, or a perigon.
      • Angles that are not right angles or a multiple of a right angle are called oblique angles.

1999

  • (Wolfram Mathworld , 1999) ⇒ http://mathworld.wolfram.com/RightAngle.html
    • QUOTE: A right angle is an angle equal to half the angle from one end of a line segment to the other. A right angle is [math]\displaystyle{ \pi/2 }[/math] radians or 90 degrees. A triangle containing a right angle is called a right triangle. However, a triangle cannot contain more than one right angle, since the sum of the two right angles plus the third angle would exceed the 180 degrees total possessed by a triangle.