a right triangle has a 90 degree angle.
what kind of triangle has a 90 degree angle?
a right triangle
the hypotenuse is the side opposite to the 90 degree angle in a right triangle; it is the longest side of the triangle and one of the two sides adjacent to angle "a". the adjacent leg is the other side that is adjacent to angle "a". the opposite side is the side that is opposite to angle "a". the terms perpendicular and base are sometimes used for the opposite and adjacent sides respectively.(see below under mnemonics).





















































the reciprocals of these functions are named the cosecant (csc), secant (sec), and cotangent (cot), respectively:
trigonometry
flies typically hold their halteres at a 90 degree offset. to visualize this, if you were to imagine a person holding their arms out sideways, this would be a 180 degree offset. if that person then moved their arms backward so that the angle created between their fingertips and spine was 90 degrees, this would be a 90 degree offset. the halteres of flies work the same way. they are positioned behind their bodies, forming a 90 degree angle between the haltere bulbs and the center of their thorax. it is necessary for the halteres to be positioned like this in order to detect the three axes of motion. those axes are yaw pitch and roll, as illustrated in the above figure (directions of rotation). the mechanoreceptors at the base of the halteres are only able to measure force in two directions (horizontal and vertical), so a single haltere is only able to measure rotations along two of the three axes. because the halteres are set at different angles (90 degree offset), they also beat along two separate horizontal and vertical axes. this gives them the ability to acquire information from two non-parallel planes and allows sensation of rotation in all three directions. however, flies are most sensitive to pitch.
halteres