The right triangle defined by the three angles: , and is a special triangle that has meaningful properties in mathematics.
The general form of the triangle, shown below, is given in terms of , where the adjacent and opposite sides are of length .
The same triangle can also be measured in radians, where radians is equal to a full rotation.
Radians are a unit that measure angle using the radius of a circle. One radian is equal to the amount of rotation required to travel the length of one radius along the circumference of the circle.