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 radians or . 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
total possessed by a triangle.
A right angle is conventionally indicated in a diagram by a small square called a right-angle marker (Marecek et
al. 2020, §9.3).
The patterns of cracks observed in mud that has been dried by the sun form curves that often intersect in right angles (Williams 1979,
p. 45; Pearce 1990, p. 12; Steinhaus 1999, p. 88).
radians or 
. 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 
total possessed by a triangle.
