Pythagoras
Pythagoras discovered the means for measuring the length of sides of a right angle.
pythogoras
Euclid.
In 1905, Dr. howard Rober and A. Cieszyski who was an engineer discovered the bisecting technique.
It was Pythagoras and his theorem about right angle triangles.
It is Pythagoras' theorem that is applicable to any right angle triangle.
Ancient Egyptian and Babylonian mathematicians lacked the concept of an angle measure, but they studied the ratios of the sides of similar triangles and discovered some properties of these ratios. The ancient Nubians used a similar methodology.
Pythagoras discovered that for any right angle triangle its hypotenuse when squared is equal to the sum of its squared sides.
Right angle, obtuse angle, acute angle, supplementary angle, complementary angle, interior angle, exterior angle, adjacent angle
The angle of incidence
the angle of incidence is the initial ray angle and the angle of reflection is the reflected ray angle