The undefined term used to define an angle is known as a trigonometric ratio. Trigonometry is a branch of mathematics that helps us to measure angles and distances. It is used to calculate the sides and angles of a triangle, as well as other shapes. By understanding the trigonometric ratios, it is possible to calculate the size of an angle without the need for a protractor.

## Defining the Undefined

Trigonometric ratios are the ratios of the sides of a triangle to the angles in the triangle. These ratios are used to calculate the size of an angle without having to measure it directly. The most commonly used trigonometric ratios are sine, cosine, and tangent. Each of these ratios is defined by the angle and the length of the triangle’s sides.

By understanding the trigonometric ratios, it is possible to calculate the size of an angle without the need for a protractor. This is because the ratios are based on the length of the sides of the triangle, which can be easily measured.

## Exploring Angles

In addition to calculating the size of an angle, trigonometric ratios can also be used to calculate the size of a triangle. By understanding the ratios, it is possible to calculate the length of the sides of a triangle, given the size of the angles. This is because the ratios are based on the length of the sides of the triangle.

Trigonometric ratios can also be used to calculate the area of a triangle, as well as the angle of a triangle given the lengths of its sides. This makes trigonometric ratios a powerful tool for solving problems involving angles, triangles, and other shapes.

In conclusion, the undefined term used to define an angle is known as a trigonometric ratio. By understanding the ratios, it is possible to calculate the size of an angle without the need for a protractor. In addition, trigonometric ratios can also be used to calculate the size of a triangle, the area of a triangle, and the angle of a triangle given the lengths of its sides. This makes trigonometric ratios a powerful tool for solving problems involving angles, triangles, and other shapes.