This section covers trigonometric ratios and metric relations in right triangles, the laws derived from them, trigonometric functions and metric relations in circles.
Trigonometry studies the relationships between the sides and angles of a triangle, as well as the trigonometric functions derived from these relationships.
It is possible to find the measures of unknown sides and angles in a right triangle using trigonometric ratios.
A trigonometric ratio is a ratio between the measures of 2 sides of a right triangle.
These ratios can be used to find missing measures, whether a side or an angle.
In a right triangle, the trigonometric ratios specify a ratio between the lengths of 2 sides.
In other triangles, the relationships that connect the lengths of the sides and the measures of the angles are of interest.
The unit circle is used to study trigonometric functions and to determine trigonometric identities.
Metric relations express the relationships between the different measures of a geometric figure.
In right triangles, metric relations express relationships between the different side lengths of the triangle, the height relative to the hypotenuse and the projections of the legs of a right triangle onto the hypotenuse.
For other triangles, there are different formulas for calculating the area based on the lengths of the sides and the measures of the angles.
In circles, metric relations express relationships between the various measures associated with them: central angle, radius, chord, arc, etc.