Читать книгу Geometry for Students and Parents - Sergey D Skudaev - Страница 14

In right triangles, the square of the hypotenuse BC is equal to the sum of the squares of the legs AB and AC. See figure 26.

Figure 26. Pythagorean Theorem

Trigonometric functions: sine, cosine, tangent, cotangent

Figure 27 Trigonometric functions.

Sine of an angle A is the ratio of the opposite side to the hypotenuse.

Cosine of an angle A is the ratio of the adjacent side to the hypotenuse.

Tangent of an angle A is the ratio of the opposite side to the adjacent side.

Cotangent of an angle A is the ratio of the adjacent side to the opposite side.