This section looks at Sine-Cosine-Tangent within the field of triangle.
A right-angled triangle is a triangle in which one of the angles is a right-angle. The hypotenuse of a right angled triangle is the longest side, which is the one opposite the right angle. The adjacent side is the side which is between the angle in question and the right angle. The opposite side is opposite the angle in question.
Sine-Cosine-Tangent are the main functions used in Triangle and are based on a Right-Angled Triangle.
The functions ‘sine’, ‘cosine’ and ‘tangent’, or as they are more commonly know ‘sin’, ‘cos’, and ‘tan’, can be used to find missing sides or angles of triangles. These functions are defined as the ratios of the different sides of a triangle. The symbol “θ” is used to describe an unknown angle.
Sine originally meant chord. create a circle with a diameter equal to one unit. Inscribe an angle in that circle. The sine of that angle is the length of the chord it subtends. All angles having a vertex on the circle and subtending that chord necessarily have the same sine. Inscribe the angle so that one of its sides is the diameter of the circle.
The sine of an angle=the length of the opposite side and the length of the hypotenuse
The cosine of the angle=the length of the adjacent side and the length of the hypotenuse
The tangent of the angle=the length of the opposite side and the length of the adjacent side.
Angle C is a right angle, indicated by the square drawn at that vertex (a vertex is where two sides meet).