O triangle is the simplest figure and one of the most important in the Geometry. It has properties and definitions according to the size of its sides and the measurement of the anglesinternal. As for the sides, the triangle can be classified as follows:
Equilateral:have all sides with equal measurements.
Isolsceles: it has two sides with equal measurements.
Scalene:have all sides with different measurements.
As for the angles, the triangle can be:
Acuteangle:it has internal angles with measurements smaller than 90º.
Obtuse angle:it has one of the angles measuring greater than 90º.
Rectangle:it has an angle measuring 90º, called a right angle.
At the right triangle, there are some important relationships. One of them is the Pythagorean theorem, which reads as follows: "The sum of the squares of the legs is equal to the square of the hypotenuse".
At trigonometric relations existing in the trianglerectangle admit three cases: sine, cosine and tangent.
Sine = opposite leg
hypotenuse
Cosine = adjacent leg
hypotenuse
Tangent = opposite leg
adjacent leg
Let's determine the relationships according to the triangle BAC, which has sides that measure a, b, and c.
sineB = B
The
cosineB = ç
The
tangentB = B
ç
sine C = ç
The
cosine = B
The
tangent C = ç
B
by Mark Noah
Graduated in Mathematics
Source: Brazil School - https://brasilescola.uol.com.br/matematica/trigonometria-no-triangulo-retangulo.htm
